My Little Sister Is the Best F*p Material - Volume 7 Chapter 03: Pure

Volume 7 Chapter 03: Pure

Tapping the tip of my folded umbrella on the floor, small water droplets appeared on the gray pavement. The number of people passing through the station seemed fewer than usual—on a humid, rainy day like this, most avoid going out.

I was here for a study session with Yamamoto-san at a café in the city. I felt a twinge of guilt for not doing something fun with Miyu instead, but dragging her out in the rain felt wrong, and since it was Yamamoto-san, this was the compromise.

“Sotomichi-kun, over here!”

A lively voice called out, and I spotted a girl with a voluptuous figure that seemed oblivious to the strain it put on men. Her shirt and flared skirt looked pure at first glance, but the high-waisted skirt accentuated her shirt, creating a stunning display of her chest.

“Sorry to keep you waiting.”

“No worries! The anticipation of when you’d show up was fun.”

Yamamoto-san immediately clung to my arm. In this muggy weather, the heat from her cleavage radiated through her bra. With her over-100cm bust pressed against me, even Miyu’s apron-clad curves excite me—there’s no way this doesn’t stir my lust. It’s practically a weapon. She’ll get stopped at customs one day.

“Let’s go, Sotomichi-kun.”

Without hesitation, she linked hands with me and headed for the ticket gate. Since our karaoke sex, she’s seemed liberated, fully committed to satisfying her love for me. Gone is the demure girl from our shopping date—she’s back to the vibrant Yamamoto-san from when we handed out worksheets as class reps.

“The train’s coming soon.”

“On a humid day like this, AC is extra tempting.”

The train’s announcement echoed on the platform, a lukewarm breeze ruffling her long hair. We exchanged mundane chatter and boarded the train two minutes later. Suddenly, people gripping the straps turned to look, followed by those in seats noticing us. I’d never felt so many eyes on me.

I’d gone out with Yamamoto-san in sexy outfits before, but I hadn’t noticed the stares because they were all on her. I was just some irrelevant guy by her side, not seen as her lover.

But her attitude toward me has changed, and so has how we’re perceived. A beautiful girl like her being so affectionate with a plain guy like me naturally draws envy. Parading her idealized, erotic body in this sultry season makes me public enemy number one. It’s proof our relationship has crossed from friendship into lover territory.

“Does it bother you?”

Yamamoto-san leaned closer, smiling. Someone like her must be used to men’s stares. I never realized how much attention could weigh until now.

“It’s scary, guilty, hard to describe.”

I whispered back. The gazes weren’t just jealousy or admiration—some carried ulterior motives, thinking if a guy like me can date her, they might have a shot. If I were her boyfriend, I’d hate her being seen by other men.

“I’ve had weirdos approach me on dates before, but most are just thinking, ‘Nice, cute girlfriend.’”

“You’ve heard them say that?”

“Nope. But I’m sure they’re thinking it.”

Her bright grin, showing white teeth, shone like before. Her confidence in her charm was quintessential Yamamoto-san, and I loved it.

Thinking back to our class rep days, she was always self-assured. Her interest in me sparked because I only saw Miyu as a woman. Over time, she became more girlishly reserved… When I first visited her place, she genuinely worried her charm might make me cheat.

Her recent demureness might stem from her few failed romances, making her cling to me. She’s been dumped plenty but likely never failed to start a relationship. Her regained brightness could be forced cheer, though she doesn’t seem that way now.

Even walking through the city, her clingy lover-like behavior drew constant curious eyes. It continued in the café, where even guys at couple tables awkwardly shifted to catch a glimpse of her.

“Reservation for the second-floor seats?”

At the café, we were led to a sofa area upstairs. The low kotatsu-style tables had L-shaped seats, partitioned by walls, shielding us from view unless staff or customers passed by. It felt private, perfect for close moments without embarrassment. Passing by, I noticed other couples cuddling and squirming.

“We’re here to study, right?”

I asked, sitting beside her.

“Of course.”

Her soft, cotton-wrapped chest jiggled as she answered.

“But if you get horny, Sotomichi-kun, I’m ready anytime.”

With a sly wink, she pulled study materials from her bag. Her brazen lust, even now that I’m closer to Miyu, frustratingly feels so appealing. The hornier a girl, the better.

Since Miyu’s been exposed as a horny girl, I wish she’d throw her lust at me like Yamamoto-san. I haven’t seen erotic-mode Miyu in a while. I worried her instincts would go wild once we started having sex, but she only gets clingy during sex or morning cuddles. What’s missing? This is a serious issue.

“Worried about something?”

“Oh, no, it’s nothing. Shall we start?”

We ordered drinks and snacks from the waiter and began studying. Yamamoto-san stuck close, already in full couple mode.

Her soft skin pressed against me, filling some parched part of my soul. Miyu’s lovey-dovey moments alone aren’t enough. I’ll have to get erotic-mode Miyu to serve me when I’m back.

“Is it okay to study so openly?”

“No problem. The manager’s cool with it.”

Apparently, she knows the manager from helping out when the café opened, earning her preferential seating. In this SNS era, her presence alone is a marketing boon.

“Let’s start with world history.”

Once our food arrived, we dove in. She pulled out a custom notebook, focused on the next school exam but packed with extra info not covered in class.

“History’s easier if you memorize it all.”

It was more serious than I expected, but I leaned into her lecture. Input from textbooks, output via practice questions—standard stuff, but having her correct my thought process without obsessing over scores made it oddly engaging.

“Is this notebook what you use to study?”

“Made it for friends. Personal tutoring comes with perks.”

As expected from Yamamoto-san, who’s way beyond exam level. Her living as a normal high school girl was shaped by past struggles. I wonder if meeting me and Miyu changed her outlook.

We continued earnestly, moving to math. I felt ashamed for assuming this was a sex-driven study session—she was an excellent teacher.

“Equations are my weak spot.”

“I’ll teach you an easy way. Some formulas you just memorize, others you understand from their roots.”

Unlike her, who could memorize everything, she explained in a way even a study newbie like me could grasp. Her math notebook laid out concepts systematically.

“For calculus equations, like in derivatives, you mainly convert combined formulas into forms where real values can be plugged in…”

“That’s way too advanced—my brain’s rejecting it.”

“Just relax, skim the reference notes, and listen.”

Somehow, her reference notes boosted my learning speed, and her teaching efficiency shone within an hour. People pay for services like this. Even calculus and vectors felt conquerable. I felt guilty getting this for free.

“Let’s take a break.”

We ordered drink refills and lunch, putting away study materials. The café’s lunch was visually stunning, feeling luxurious, though pricey.

“What do you usually do, Yamamoto-san?”

I dug into her private life, something I hadn’t explored much. As pizza and pasta arrived, I split them while she pondered.

“On weekends, I often hang out around here. Sometimes with friends, sometimes just wandering alone. Walking around, I get hit on or scouted a lot, so I end up in department stores or cafés.”

“Still getting approached?”

“Regulations cut it down, but some guys find loopholes.”

Despite our intimate time together, I didn’t even know how often she goes out. Outside school, I’ve spent more days having sex with her than not.

What an unhealthy relationship. But doing couple-like things now, don’t we look a bit like a pure, dating pair?

“Do you ever stay home all day?”

“Quite a bit. Especially lately.”

Yamamoto-san gazed at me with dreamy eyes.

“I’ve been masturbating more…”

Her candid confession, laced with an increasingly sultry vibe, tipped my feelings from unease to eager anticipation for sex.

“That sounds tough.”

I dodged the risky topic and finished eating. Once the table was cleared, we spread out our study materials again.

“This is super late to ask, but at school, you’re supposed to have no experience with guys, right?”

“I’ve never explicitly said anything, but friends ask if I’m interested.”

“What do you say?”

“I’m looking for my ideal guy.”

As she spoke, she leaned closer, resting her hand on mine. Her girlish, endearing demeanor was irresistible. Is it a sin to feel deep joy as a man facing such a beautiful girl?

“Anything to watch out for when school starts?”

“It’s fine. Even when rumors about us spread, everyone’s so used to gossip they don’t believe it.”

So that’s why my rumors fizzled out. I worried about running into someone at the station, but since Yamamoto-san is the “pure, cute girl who’s friendly with everyone,” it doesn’t become a big deal.

“So, don’t worry.”

Grabbing my arm and pressing closer, she pushed her chest against me, flaunting their roundness as they squished. I thought it was just pent-up lust, as Miyu suggested.

“Uh, Yamamoto-san…”

It was my oversight. On closer inspection, she wore only a bra under her shirt. In the rain, it could turn see-through—such a bold choice. I couldn’t help but gulp.

“So, what else do you do with friends?”

No one would blame me for sleeping with her, but with Miyu as my girlfriend, I couldn’t give in easily, so I distracted myself with small talk.

“We hang out, but this summer, I’ve been helping friends find boyfriends.”

“Helping with boyfriends?”

“It’s our second-year summer—everyone wants memories and to get frisky.”

She whispered the reality. At our age, hormones are raging. But with a beauty like her, doesn’t she outshine everyone?

“When you’re a prize like me, there’s a way to make them pick the runner-up.”

At the beach, there are groups of guys, and she gets invited to mixers disguised as “exchange events.” Kawafuji’s often involved. Helping friends find boyfriends lets her curry favor and dodge unwanted guys.

To make them choose the runner-up, her friends spread fake info to their target guys, saying, “Yamamoto-san’s after the guy next to you.” Harsh, but her presence flattens other girls’ appeal to “Yamamoto-san or nothing.” When she chats with another guy, it sparks panic—“My friend might get a girlfriend”—prompting guys to lower their standards and approach others.

“Does that really work?”

“Guys are just as desperate.”

Her hand subtly slid to my knee. Her teasing, piling up like body blows, was steadily hardening my penis.

“R-Right, learned something. Shall we get back to studying?”

I considered calling out her escalating touchiness but didn’t think I’d win, so I chose retreat. Even knowing it’d turn sexual, my rationality balked in public.

“Hehe.”

But Yamamoto-san clearly had no intention of studying anymore.

“By the way, in those groups, the real prize flower’s actually into the guy right next to her.”

She tickled my ear with her breathy reply, pushing the notebook away. With the erotic teacher finally here, my cock swelled eagerly.

“Any students who’d rather have sex than study?”

Taking advantage of our closeness, she teased in a low voice. Her sultry, teacher-like tone made my dick raise its hand uncontrollably.

“Sotomichi-kun’s little friend is honest. The teacher fully approves, so let’s get to it.”

Without hesitation, she unzipped my pants and touched my penis, teasing the now-hard, confined shaft through my underwear.

“Y-Yamamoto-san, in a place like this…”

“You love it, Sotomichi-kun. Miyu-chan’s okay with it, right?”

She undid a shirt button, flaunting her bra through the gap. It was a front-hook bikini style, easy to slip a hand into for nipple play—underwear made for sex.

No way my hand could resist such perfect erotic lingerie. As I teased her hardened nipple, she shivered, letting out joyful gasps.

“Nn… ahn…!”

Unconsciously, I kneaded her breasts. Despite being in a café—no, because we were in a café—I gripped them firmly to stoke her arousal. As she said, I love doing this with her here. With Miyu’s permission, there’s no need to hold back.

“Get nice and worked up, Sotomichi-kun.”

She pulled my boxers open, freeing my cock. Happily stroking the upright shaft, she then gripped it gently with her whole palm.

“You know my ears are sharp, right?”

She could hear waiters approaching or customers moving. That’s why she could be so bold without getting distracted. For kinkier folks, the lack of thrill might disappoint, but we’re normal. We’re only doing it here because we got horny.

“Yamamoto-san, this feels too naughty…”

Even as I said it, I undid another button, letting her breasts spill out of her bra. Now we’re even. She kept stroking my cock.

“You’re super naughty too, Sotomichi-kun.”

She slipped a hand under her skirt, dropping her lace-and-string panties to the floor. Panting like an excited dog, she scooped her love juices and smeared them on my cock. The slick shaft, nerves heightened, seemed to echo wet sounds through the café.

Her provocative act ignited my competitive streak. Unlike the restrained sex with Miyu, knowing I could unleash my lust here drove my hand under her skirt. Her pussy was as wet as Miyu’s, and slipping a finger in, bending it toward her abdomen, drew a lewd squelch.

“Aah… no, Sotomichi-kun… such loud sounds…”

Her sharp senses let her keep sounds just below noticeable while stroking me, but I, clueless, churned her hot vagina messily. Any trace of her purity was gone—she was just an erotic girl letting me grope her while jerking me off.

“Nn, nnh… ah—!!”

She let out a moan, her shame reddening her face. She stifled it to a throaty whimper, but a waiter, sensing something, came up to check.

“Would you like more water, sir?”

We gave awkward smiles, declined, and the waiter bowed lightly, moving to the next table. We’d fixed our clothes just in time, hiding my erect cock with her shawl, narrowly escaping trouble.

“…Ended halfway, huh?”

Yamamoto-san’s expression was tinged with loneliness, yet her eyes sparkled. She must’ve really enjoyed our earlier play. She’s probably a pervert.

“Should we change the study session location?”

Her suggestion instantly brought a love hotel to mind, and it seemed she thought the same. After settling the café bill, we headed to a love hotel for our next “study spot.” To think I’d visit one twice before ever going with my girlfriend—what a bizarre life I lead.

“This is the best-of-the-best love hotel, always coming up in friends’ love talk.”

The building was conveniently close, as if predestined. A green sign at the entrance listed rates for rest and overnight stays—undeniably a place for sex.

“So schoolmates use this place a lot…?”

“I checked friends’ schedules, so it’s fine. If their acquaintances show up, we’ll deal with it.”

A love hotel’s quality is hard to judge from a clean entrance or online photos. An indefinable datedness can ruin the vibe. Yamamoto-san didn’t want our first love hotel together to be lackluster, so she chose this one despite the risks.

Thanks to my one prior visit, I handled room selection and prepayment smoothly, taking the key and riding the elevator with her.

“Have you come here with Miyu-chan?”

“Nope. Now that you mention it, coming to a love hotel with my sister feels…”

“I think it’s fine.”

Chatting, we reached the room, opened the double doors, and set our bags near the sofa.

“Getting called ‘Onii-chan’ in a love hotel feels decadent. I’m a bit jealous.”

Her playful yet sultry tone sent my cock, already on edge, swelling rapidly.

True, an “Onii-chan” call in a love hotel hits hard. If we could bring a uniform, I’d love to sit Miyu on that queen-sized bed in her school outfit, having her call me “Onii-chan.”

Miyu would never allow sex in a uniform at a love hotel, though. Just imagining it makes me want to come.

“You’re already reacting.”

Without warning, Yamamoto-san slipped her hand into my pants, gripping my penis and stroking it.

“W-Wait, that’s bad… if you do that now…!”

“Sotomichi-kun, you come so fast thinking about Miyu-chan. Doesn’t that cause issues during regular sex?”

With a mischievous smirk, she pulled my pants and boxers down, crouched, and engulfed my cock.

“Nn… nchu… chubu… ngu…!”

Like she was starving, she sucked me eagerly, making vulgar sounds, her lewd gaze a stark contrast to her pure outfit.

“Aah… aaah… Yamamoto-san… no way…!”

After all the teasing at the café, thinking of Miyu and getting a surprise blowjob, I came in an instant.

“Nfu. Nope.”

But after a few strokes, she released my cock. The sudden coolness deflated my near-climax erection.

“Forget why we came here?”

In this state, she started setting study materials on the table. I stood there, half-naked, with a frustrated erection and nowhere to go.

“Time to review. Sit here.”

She took my hand, not letting me pull up my boxers, and sat me on the sofa, her bare crotch exposed. She crouched between my legs, looking up.

Her upturned gaze was cuter than ever, her purity amplified. Having such a beautiful girl’s busty shirt so close to my groin made my cock throb.

“Solve one big question in five minutes.”

She rubbed my cock, leaning closer, holding a phone timer in her right hand.

“Yamamoto-san, this might be bad.”

“Hm? Why?”

“I probably can’t hold back.”

Whispering my confession, she hid a smirk behind a puffy, mock-angry face.

“Did you do something like this with Miyu-chan? You two are such a horny couple.”

Her lecture ignored her own lewdness, leaving me speechless. She sighed, lowering her brows in resignation.

“Since you can’t hold back, I’ll just lick.”

She extended her tongue, carefully licking my balls and shaft.

“Ah… aah… feels good…”

Licking alone wouldn’t make me come, but it was torturous. Still, she mercilessly started the timer, urging me to pick up the pen.

“Until you solve it in five minutes, it’s like this.”

She began the blowjob without debate. Each lick tightened my erection, straightening my spine.

Such intense pleasure could drive me insane. I had to solve the problem fast.

(It’s fine, just two familiar transformations… I can do this…)

I scanned the equation, but two seconds later, the text blurred. The low love hotel table let me see her sucking me. A girl’s face during a blowjob looks oddly youthful, her pure outfit amplifying her innocence.

Yet, in a love hotel, the act was utterly obscene. She licked my balls greedily, savoring the precum that oozed out.

“Yamamoto-san, it’s no use. My brain’s not working.”

“Nn… come on, Sotomichi-kun… I want to suck you so bad… try harder… chu, lick…”

Trying to recall formulas, each glide of her tongue on my cock’s underside numbed my brain, focusing me on my groin. Within three minutes, my mind was consumed by the urge to come.

“Let me come once… I’ve been holding back since the café…”

“I know. Licking your tip, it’s such a thick taste.”

She gave me a longing look, licking my cock with her rough tongue fully extended.

“I want to taste your cum again, Sotomichi-kun…”

Her raw lust resonated in my groin. I wanted to pour all my pent-up semen into her wide-open mouth.

“Five minutes up. Solved it?”

“Nothing yet…”

“Alright, try again.”

Her blowjob lessons were relentless. By the third round, I adapted enough to write partial solutions, but memory-dependent parts stalled as my brain shut down.

Thinking wasn’t fast enough. I needed to reflexively derive transformations from equations to solve while enduring her blowjob.

(Expand this form… lower this exponent… ah… aaah, no… I’m gonna… come…!)

Initially gentle, her licking grew desperate, sucking my glans just shy of making me come. Not quite ejaculating, but at my limit, I leaked more than precum, and her excitement peaked as she drank it. On the sixth try, I finally solved it in time. Reluctantly, she released my cock, stood, straddled my knees on the sofa, and glanced at my answer.

“Good job, Sotomichi-kun.”

She petted my head, pressing my face into her chest, then whispered.

“The coefficient in the last part of the second question… might be off…”

She used vague words, avoiding looking back. I caught her feigned ignorance, fixed the mistake, and she eagerly marked it correct.

“You solved it properly, Sotomichi-kun. Time for your reward.”

It’s unclear who the reward was for. She steamrolled ahead—if she was so desperate, she could’ve just had sex. Getting off the sofa, she pounced on my cock like a starved beast.

“Guchu, chubu… haa… Sotomichi-kun’s… so hard, I love it… nn… ngu… juru!!”

“A-Aaah… Yamamoto-san… I really can’t hold on…!!”

“Nchu, nmu… it’s fine… come… let it all out…!!”

Wrapping her arms around my waist, she latched onto my groin, taking me to the base, her tongue writhing as she sucked. Her full-throttle lust overwhelmed me in seconds. As semen surged from my balls, my cock hit peak hardness, a jelly-like sensation shooting through my abdomen.

“Haa… aah… I’m coming, Yamamoto-san… coming…!!”

A thick sound echoed inside me, and I ejaculated like I was urinating in her mouth. The unrestrained semen flooded her throat with such volume and odor that she couldn’t hide her gagging. Pulling my brutal cock from her teary-eyed mouth, white fluid pooled over her tongue.

“Ugh… uuu…”

Since sleeping with Miyu, my semen had grown thicker, too much even for Yamamoto-san to swallow easily. Still, she chewed to reduce its viscosity, timed her breaths, and gulped it down in one go.

“Ngu… haa… this awful taste… feels like I’m really having sex with you… I love it…”

Exhausted, she collapsed onto my lap. My still-erect cock stood tall beside her face.

“What’s with this energy? Haven’t you been getting any lately?”

“Not really. Just haven’t come since yesterday afternoon.”

It’s probably her pure outfit and lewd acts. Her clothes, similar to Miyu’s, make my instincts react to her, already so like Miyu.

“Maybe you can still come?”

“If you ask, I can probably come a lot.”

Oddly, I felt ready for more. Hearing this, her eyes lit up, and she leapt onto the sofa.

“Then let’s have more sex, Sotomichi-kun!”

Her exhaustion vanished, and with no intention of returning to studying, Yamamoto-san scooted closer on the sofa, pressing her hips against mine. A slick, distinctly different sensation from saliva coated my penis, feeling like it was being licked. Hidden by her skirt, I couldn’t see, but it didn’t feel like it was through panties.

“No panties?”

“Not since I took them off at the café. You were horny, Sotomichi-kun, and I wanted to be ready for you to slide in whenever.”

Her massive breasts jiggled as she spoke shyly, all while rubbing her slit against my cock. They say male arousal comes from visuals, but being teased in a way I couldn’t see was incredibly stimulating.

“R-Raw… isn’t that risky?”

Honestly, I wanted to plunge into her exquisite pussy, which could make any man finish instantly. The urge to sink deep, press my glans to her entrance, thrust in, and creampie her was undeniable.

But I have a proper girlfriend, so I had to temper this passion. Though raw sex wasn’t explicitly forbidden, I felt it was wrong to do it with another woman before Miyu.

“I can’t get pregnant right now, so that’s fine.”

Her unexpected reply. Wait, didn’t she say something similar during our karaoke sex?

“You’re on the pill?”

“It’s a condition for having sex with you, Sotomichi-kun. Creampie all you want.”

She delicately lifted her skirt’s hem with both hands. I’m not against sex, but initiating it myself felt like betraying Miyu.

“There’s a condom on the tissue box. Let’s put that on first.”

I suggested it to move things along. That way, we could slide into sex without overthinking.

But Yamamoto-san didn’t budge from the sofa, just kept sensually grinding her pussy against my cock.

“Um… it’d really help if… you forced yourself on me…”

Despite loving sex, she turns passive when it comes to intercourse. It’s not just a rape fantasy—recently, she seems to be deliberately avoiding penetration.

“Is there a reason you can’t do it?”

Her attitude was obvious, so I asked directly. She nodded, unsurprised, as if expecting the question.

“Is Miyu forbidding it? She hasn’t told me anything.”

If penetration was off-limits, Miyu would’ve said so. Assuming that wasn’t it, Yamamoto-san gave an ambiguous nod, neither confirming nor denying.

“It’s not forbidden… but I can’t bring myself to do it… It’s a vague promise now…”

Her nuanced response suggested a self-imposed vow she could break if she wanted. In this moment, with our genitals pressed together, she could easily slip me inside and call it an accident, but she showed no inclination.

At least it involves Miyu. Could it be tied to the letter Miyu mentioned yesterday? That letter seems to make Yamamoto-san’s affection for me push her toward giving up. Is banning intercourse a way to draw a line between us and lovers? That would explain why she called it a breakup letter, but it doesn’t fully add up. There’s got to be another concrete reason.

“Forcing myself on you… sorry, that’s tough. What do you want, Yamamoto-san?”

I’ve “forced” Yuka before, but that was on Miyu’s orders. If I ever felt that urge myself, it’d only be with Miyu, losing control.

“I want… you to come inside me…”

Apparently, she’s never been creampied. Guys might think saving firsts is better, but for girls, it seems they want to give them to someone they truly love ASAP.

But it’d be my first time creampying too, and I want that with Miyu. She understands that.

“How about this?”

Still facing me on the sofa, she began rocking her hips back and forth. Unlike grazing my underside, she clamped my cock with her inner labia, sliding the entire surface from base to tip.

“T-This is…”

I’ve done something like this with Miyu, and rubbed against Yamamoto-san from behind during karaoke sex. But this was my first proper intercrural sex with a girl taking the lead. Even with her on the pill, the raw contact was thrilling.

“Nn… ah… it really… lets me feel your hard cock, Sotomichi-kun…”

Grinding back, her clit rubbed my penis, sending her pleasure too. Just having my cock against her pussy heightened her arousal. That’s why Miyu never initiated intercrural sex. For Yamamoto-san, who craves feeling my raw cock, this was her only option.

“But… coming inside…”

Intercrural sex could be excused as “not real sex,” but ejaculating in her vagina would count as a creampie, defeating the point.

“So… in the back…”

What she wanted was for me to come in her anus.

“Before, there was that little accident, right? It felt amazing.”

During karaoke sex, I accidentally came in her ass. Now, she wanted it intentionally, as a substitute for vaginal creampies.

“I cleaned up before leaving the café. And I’ve been loosening the entrance a bit during solo play.”

In her fantasies, she’s had me come in her ass countless times. Coming to a love hotel made her desperate to make it real.

“Got it. When I’m ready, I’ll come in your back hole.”

Her compromise was fair—I’d be a lousy guy not to go along. With my consent, she intensified her hip movements.

“Ahn… ah… Sotomichi-kun…!”

Intercrural sex is one-sided service, yet it pleasures her too, making it perfect for her.

Both still clothed, only underwear off, her endlessly flowing juices made muffled splashing sounds under her skirt.

The sound and feel were as rich as vaginal sex, amplified by her pure, beautiful exterior, making the lewdness stand out sharply. Her breasts, once subtly swaying, now bounced heavily before my eyes, captivating me.

“Ah… aah…!”

Her erogenous zones drowned in pleasure, my instincts stirred by visuals, my recently ejaculated cock already prepping for another round. The urge to bare her chest clashed with wanting to ravish her pure body, leaving my confused hands frozen.

I was just letting her have her way. But that suited us both—my pathetic, one-sided defeat was our ideal sex.

“S-Sotomichi-kun… ahn… n-no… I’m gonna… come…!”

Her body trembled faintly, yet she couldn’t stop moving. To come so quickly, Yamamoto-san must have been incredibly pent-up. The unique pleasure only I could give her drove her to seek it greedily.

Her black hair swayed at the edge of my vision, her massive breasts surging like waves before me. Her pure, shirt-clad appearance triggered some illusion in my brain, blurring my senses.

“Yamamoto-san… I’m… already…!!”

It wasn’t the usual rising urge to ejaculate. But instinctively, I knew. My brain, easily fooled for the sake of coming, recognized her as a valid target based on past experiences and her resemblance to Miyu. All it needed was the trigger.

“It’s okay… let it out…!”

As if she understood, Yamamoto-san whispered those words in my ear. The same words Miyu had commanded me to come with countless times. For me, they’d become a switch for ejaculation.

“Yamamoto-san… I’m coming… inside…!!”

Timing her forward thrust, I wrapped my arms around her and inserted my erect cock into her anus.

“Aah… aaah… kihya… ahh!!”

It was tighter than her vagina, with stronger resistance. Yet, her self-trained anus, softened and pliant, warmly accepted my cock.

“Coming… coming…!!”

The raw, unrestrained ejaculation filled my brain with pleasure chemicals, not from physical sensation but from the fact of unloading inside her.

“Sotomichi-kun… you’re coming… inside me… ah… nnh…!!”

It was the same for her. The thrill of even just the tip in her anus pushed her to climax, as if it were her first anal sex.

As my ejaculation subsided, she lifted her hips with a dazed expression, pulling my cock from her anus.

“Sotomichi-kun creampied me…”

Though fully clothed, looking normal post-sex, knowing my semen remained under her flared skirt sparked a joy too intense to call mere afterglow.

“Are you satisfied, Yamamoto-san?”

She seemed to have come from the thrill of raw penetration, but her drenched vagina got no stimulation. I’d gotten used to pleasuring Miyu by hand and wanted to apply that to her.

“Ah, w-wait… not now… no…!”

When I slipped my hand under her skirt and inserted a finger into her pussy, she jolted with unexpected sensitivity. Probably hypersensitive post-orgasm, she looked adorable, so I pressed two fingers into her sensitive flesh, like at the café.

“Nnaah… aah…! N-No…!”

Her frail moans, unlike anything before, egged me on to churn my fingers wetly. My cock swelled again, but just fingering her pussy sated my lust.

“Ahn, ah… after you came in me… it’s gonna… leak… nn, aah…!”

Clenching to keep the semen in her ass, she couldn’t brace against the vaginal pleasure, taking the stimulation raw. I knew I should stop for her sake, but my instincts urged me to unleash my desires.

“Hya… I’m… gonna come… coming—!!”

Her second climax didn’t stop at one; each finger movement made her come again. A mischievous urge to make her leak semen took over, and I caressed her until her girlish moans exhausted her strength.

Finally, a faint “ah…” escaped her, and white fluid dripped from under her skirt to the floor.

“Ugh… Sotomichi-kun, that was mean…”

“S-Sorry. I got carried away.”

Shakily standing, she embarrassedly searched for tissues. Wanting to clean her own mess, I stayed out of it, fixing my clothes.

“You’re so naughty, Sotomichi-kun.”

Smiling in the end, she’s a healthy girl who’s happy as long as sex is fun. Today’s “study session”—if you can call it that—was a big success for her.

With rest time left, we gave up studying and cuddled on the bed, not sleeping, just relaxing. Lying beside a beauty like her made me feel fulfilled as a man. It sounds smug, but this kind of happiness is hard to match. That I can resist choosing her because of my girlfriend makes me kinda admirable, right?

“I need to get satisfied soon…”

Yamamoto-san mumbled at the ceiling. Her lack of emotion in those words caught my attention. Like Miyu, she occasionally exudes an odd aura.

For us, this time is a grace period from Miyu. A concession to let Yamamoto-san, hurt by my rejection, satisfy her love for me. That’s the only way to see it, so she’s committed to being affectionate with me.

“Hey, wanna go on a date tomorrow?”

She gazed at me with the suggestion. Not a study session pretext, but a normal outing to enjoy together.

“Tomorrow, huh?”

Miyu’s likely on her period, and she mentioned helping Haruka’s job. This is perfect timing. Considering Miyu’s plan, it’s an ideal invite.

“Sure. Where to?”

With Miyu, we planned a hot spring and aquarium. I’d prefer somewhere else.

“It’s summer, so how about fruit picking? The forecast says it’ll clear up by afternoon, but there’s a farm with indoor dining like a restaurant if it rains.”

“Sounds good.”

It’s the healthiest, most wholesome date yet. Walking outside should burn off some lust.

“Decided, then!”

Knowing we’d meet again, she perked up. With rest time nearly up, we left the hotel. The sky from the train was cloudy but bright, and with an odd excitement, we stood by the door despite empty seats.

That made us stand out more, and the stares were bolder than in the morning. Oddly, they didn’t bother me anymore. As she said, a cute girlfriend draws envy. Even without dating, talking alone sparks jealousy. I was in that position recently, so I get it.

“How do we look to others as a couple?”

“Dunno. Probably a mismatched couple?”

We had a similar talk on a train after work once. A plain guy toyed with by a beauty. Or they pity her for choosing a guy like me. But the reality…

“Walking around town without cleaning the semen shot in my ass, riding the train like this. I’m the slave who’ll do any naughty request.”

“No one would guess that power dynamic.”

She adores me more than any guy. That fact gives me pride and support. The stares don’t faze me because, fresh off sex with her, I’ve reaffirmed that confidence. I can’t stay a plain guy forever. I’m that cute sister’s boyfriend.

“Will dating Miyu feel similar?”

Miyu’s just as pure and busty as Yamamoto-san. The stares would be as intense. As my real girlfriend, we’d be even more lovey-dovey, and how confidently I act as her boyfriend will define the date. This experience will help with Miyu’s date.

“Hmm, I wonder.”

Surprisingly, she replied negatively—not mocking or belittling Miyu, just stating a truth.

“What do you mean?”

I asked, but she only smiled, her vibe different than usual.

“Hey, Sotomichi-kun.”

And then, for the first time.

“Tomorrow’s date will definitely be fun.”

It was a simple statement anyone might make. But Yamamoto-san, always natural, hinted at a hidden intent.

“I’m looking forward to it.”

I sensed it but couldn’t press. Being part of Miyu’s plan kept me from slipping. Looking back, I’m glad I didn’t know the full strategy—I’d have spilled if pressed.

“Yup, look forward to it. Satisfaction’s a two-way thing.”

She carried an air like when she first visited my apartment. I thought she was just accepting Miyu’s mercy, but was this a challenge?

If this is the outcome Miyu wanted…

What kind of curse was woven into that single letter?