How Using My Oppai Skill to Enlarge My Sister’s Breasts Led to Building a Harem - Chapter 21 Part 3

Chapter 21 Part 3

Side Story: Miyabi

I’ve been grappling with a problem lately.

“Ugh… so soft…!”

“It’s so big and hot, darling♡”

It’s about my nightly encounters with one of the women I love, Ayaka-san.

Munyu♡ Shuko♡ Shuko♡

Right now, Ayaka-san is on all fours, stimulating my erect cock between her soft buttocks.

“Haa, haa… Ayaka, that feels so good…!”

This is a continuation of our pretend-marriage game, where we call each other like real spouses for now.

“Aan♡ Please feel good with my body♡”

“Ayaka, Ayaka…”

I press my cock into the crevice of her plump buttocks, sandwiching it as I move back and forth. The softness, the perfect curve of her beautiful rear, and her feminine fragrance make my cock tremble uncontrollably.

“Ku… aa…! Can’t hold it… I’m cumming, cumming!!”

“Kya!? Haaan…♡ So much of your precious seed♡”

I cum hard between her buttocks, thick semen splattering onto her pale skin and the thin silk nightgown enveloping her.

“Uaa… feels amazing, Ayaka… you’re the best.”

“Ufufu♡”

Ayaka-san’s body is truly voluptuous—not fat, but an ideal feminine form with soft flesh perfectly maintained. Even now, when pregnancy prevents intercourse, she pleasures me like this.

“Next, shall I… use my breasts?”

“Yeah, let’s do that.”

Her buttocks, breasts, mouth—she uses them all to satisfy my cock. I have no complaints. I shouldn’t have any complaints.

But—

(I want to have sex… I want to feel that melting pussy.)

Deep down, my instincts aren’t satisfied. I want to connect with the woman I love from the inside, not just the outside. If her pussy is off-limits, my desire to use her other hole has been building.

※

To become worthy of the Saionji family, I’m training under Miyabi-san. Beyond studies and etiquette, I’m also undergoing physical training, including self-defense lessons.

“Self-defense, as the name suggests, is about protecting yourself,” Miyabi explains.

“Isn’t that like martial arts?”

I’ve seen martial arts matches on TV. Every boy dreams of fighting coolly like that.

“No. To protect yourself, you don’t need to defeat your opponent.”

“I see. So, just escape from danger?”

I heard somewhere that if fighting’s risky, you should flee.

“That’s not a bad first thought.”

“Then, shouldn’t I practice running?”

If I’m fast, they can’t catch me, right? I suggest it.

“If your attacker is foolish, they might let you escape. But predators often choose their hunting grounds.”

“Hunting grounds…”

“Places you can’t escape—rooms, elevators, trains, buses, dead ends, corners, local hideouts. The possibilities are endless.”

True, a sudden attack leaves no time to run. By the time you sense danger, it might be too late.

“In a fight, the one with the terrain advantage wins. Underestimate a ‘mere criminal,’ and you’re the one who gets hurt.”

“I get it…”

If someone grabs me from a blind spot, I’d be helpless. That’s why self-defense matters.

“And if someone you must protect is beside you, you can’t run.”

Her tone brings Ayaka-san to mind. If Ayaka-san or the other girls were in danger, I’d rather die than flee.

“Got it. Teach me self-defense.”

“Of course. Let’s start with footwork.”

I train under Miyabi, practicing swift movements in all directions.

“Glide across the ground—but don’t drag your soles. You’ll trip.”

We’re in the Saionji family’s training gym, with polished wooden floors, so footing isn’t an issue.

“In real combat, obstacles—pebbles, sand—can make you slip. Moving your body precisely and quickly isn’t easy.”

It’s tough. Miyabi demonstrates, gliding smoothly, but I can’t match her fluidity.

She drills me on footwork relentlessly.

“In martial arts and sports, footwork is key. Hands are dexterous—humans survived because of them. Feet, however, are far clumsier.”

True. I could mimic hand movements, but not footwork. Amateurs can’t copy soccer players’ moves.

I practice footwork as instructed, but it gets frustrating.

“Miyabi-san, don’t we practice flashier moves?”

“Flashy moves?”

“Like… high kicks?”

On TV, high kicks to the head are knockout moves.

“High kicks… like this?”

Despite her maid outfit and heels, Miyabi performs a perfect spinning high kick.

(I saw it…)

The kick was too fast, but the white fabric at the base of her thighs burned into my retinas.

“Lifting your leg disrupts balance and risks falling on uneven ground.”

“Y-Yes…”

“And—”

“If dodged, you’re wide open.”

Her spin leaves her back exposed.

“Self-defense shouldn’t create vulnerabilities, so I don’t recommend such moves.”

“Right…”

I feel bad for Miyabi’s serious teaching, but my eyes are glued to her beautiful rear.

“Let’s stop here. You seem distracted.”

“S-Sorry…”

She caught me staring at her butt. I’m embarrassed for ogling her while she taught earnestly, my face flushing.

“By the way, you mentioned a concern earlier.”

It’s a holiday, and when she picked me up, I mentioned wanting to discuss something.

“Uh, it’s… maybe later.”

The timing’s off. I don’t want to disappoint her with my issue.

“If it concerns Ayaka-sama, speak now. Delaying is disrespectful to her.”

“You’re right… Okay.”

Miyabi always prioritizes Ayaka-san. She’ll judge my concern, and I have no choice.

“Well, with Ayaka-san… could we maybe… have sex?”

“Vaginal intercourse?”

“Uh, yeah…”

Lately, our intimacy has been limited to her buttocks, thighs, mouth, or breasts. Even I’ve reached my limit wanting to embrace her fully.

“That’s not permitted. Intercourse during pregnancy risks miscarriage.”

“Ugh… right. What about her butt?”

“You mean inserting your penis into Ayaka-sama’s anus?”

“…Yes.”

Her bluntness throws me, but it’s exactly what I mean, so I can’t deny it.

“I wouldn’t recommend it. Ayaka-sama is the Saionji family’s daughter.”

The Saionji family is nobility. Asking to violate their princess’s rear is bold, to say the least.

“But under certain conditions, it might be possible.”

“Really!?”

A surprising reprieve. The conditions intrigue me, but meeting them means anal sex with Ayaka-san is on the table.

“What conditions?”

“First, you must test it on my body.”

“Your anus?”

“Yes.”

Is that okay? Anal with Miyabi is a dream, but…

“Your penis is impressive. I’ll ensure it’s safe for a first-timer.”

“Have you done it before?”

“No, I never anticipated inserting my master’s precious penis into my impure hole.”

True, with unrestricted access to her pussy, why bother with anal?

“So, it’s your first time…”

She explains that soiling her master’s cock is against maid protocol, so she hasn’t trained with toys either.

“Sorry.”

“No, it’s not… I mean…”

I’m honored to be her first anal, but nervous. Too nervous to get hard—

“Are you… aroused?”

“S-Sorry…”

No need to worry about that.

…

“Let’s do it here.”

She leads me to one of the Saionji estate’s tatami rooms.

“It’s well-ventilated, with natural light.”

It’s still daytime, so she chose this airy room over a dim bedroom.

“Excuse my unsightliness…”

Miyabi presents her buttocks, spreading them to reveal her hole.

(It’s beautiful… I’ve seen it before, but it’s not dirty at all…)

“I cleaned thoroughly, but it’s still an impure place…”

“Not dirty at all. Look… rero…”

“Hii!? Master, stop! Don’t put your mouth there!”

Miyabi panics, a rare sight. To me, her pink hole, blooming like a flower, is irresistibly alluring. My cock hardens with every lick.

Chujururu… Chupa, Rero rero rero…

“No, no… you’ll get dirty…”

“But I need to loosen it up… juju…”

I don’t do this with just anyone. It’s my first time licking an anus, but since Miyabi’s a woman I love, I feel no resistance.

“~~~Aa…”

Jurur. “Ready, Miyabi-san? I’m going in…”

I pull my mouth from her softened anus, aligning my cock’s tip with its center.

“Here I go, Miyabi-san. Fu… nn!”

“Aggh! Uuu… aa…”

My glans spreads her chrysanthemum gate, sinking halfway in. She looks pained, but my cock senses discomfort, not agony. I can keep going.

Gugugu! Gu…!!

My glans is fully engulfed. One push, and we’ll be united through her anus.

(I’m violating Miyabi-san’s ass—her perfect, superhuman ass…)

To me, Miyabi is a respected teacher, an admired woman, a flawless superhuman. And I’m taking her anal virginity. I’m the only one in the world to do so.

This fact fills me with unprecedented pride.

(I love you, Miyabi-san. Be mine…)

Violating an untouchable woman ignites an unquenchable fire in my hips.

※

<Miyabi’s Perspective>

My master’s massive penis presses against my anus. I’ve trained to receive it in my female hole for his pleasure, but never considered this impure one.

A man’s penis is sacred for procreation. Defiling it is unthinkable for a maid.

(But this is for Ayaka-sama. If it fails, he’ll give up on anal.)

Ayaka-sama is the Saionji family’s noble daughter. I doubt her delicate anus can handle such a large penis. So, I’m the test subject.

“Here I go, Miyabi-san. Fu… nn!”

His penis enters, stretching my unclean hole.

“Aggh! Uuu… aa…”

A pained moan escapes me. It’s not… painful. Considering this hole’s purpose, it’s barely manageable.

“Are you okay, Miyabi-san?”

“Y-Yes… no problem.”

I reply curtly.

“Good. I’ll go slow.”

Despite my coldness, he smiles warmly, gazing at me.

(What am I doing to such a kind man…?)

I secretly hope this fails, yet he moves carefully, mindful of my body.

“Nn… nnu, ha…”

I knew it was big, but its presence is overwhelming, reaching deep inside.

“It’s in, Miyabi-san.”

“Y-Yes…”

As a maid, I’m leaving everything to him, even plotting failure—a disgraceful act.

(I’m ashamed… to be so shameless…)

“Does it hurt? Should I stop?”

I can’t lie. I answer honestly.

“It feels full… but not painful. Continue.”

“…Got it. Tell me if it hurts.”

His kindness blinds me, my heart racing.

“Here I go…”

“Nn! Haa… nn, aa…”

(So big… his thick, strong penis moves in and out of my anus…)

Nuchu♡ Nuchu♡ Nuchu♡

“Haa… nn, it’s… a strange feeling.”

(Different from vaginal sex, an indescribable sensation.)

Like continuous excretion, almost.

“Your insides are slick and feel good…”

“Uh… th-thank you.”

Unsure how to respond, I take it as praise.

“I’ll speed up a bit.”

Nuchu♡ — Zuchu♡ Zuchu♡ Zuchu♡ Zuchu♡

“Nfu, nn… nn, nnu~!”

(The sensation… it’s continuous, fuaa♡)

Zuchu♡ Zuchu♡ Zuchu

“How is it, Miyabi-san!?”

“Ku… aa… ahaa… hau!!”

Paan♡ Paan♡ Paan♡ Paan♡

(It feels… good…♡ This dirty excretory part…♡)

“Miyabi-san, it’s sucking me in…!”

(This is wrong… why am I feeling this in my anus…?)

Unexpected. I only thought of his pleasure, not mine.

(I’m feeling good in my anus… unbelievable.)

“No…♡ Kuuun…!”

“It feels good, right, Miyabi-san!”

I’m definitely feeling it, but I shake my head, denying it.

(Feeling this in a non-sexual hole… like a pervert…)

“But your body’s loving it. Look!”

Nyu♡ — Gubo♡ Gubo♡ Gubo♡ Gubo♡ Gubo♡ Gubo♡

He pulls out once, then thrusts back in, his flared glans scraping from my anus to rectum.

“Oh♡ Kufu… faa, nn♡”

The vague pleasure turns intense.

(This is bad♡ My shameless voice is slipping out♡)

“Miyabi-san, you’re cute…”

“Ku… faa♡”

(He knows…? That I’m feeling it in my anus, that I’m a pervert…?)

I didn’t know this pleasure existed.

“Miyabi-san! Juju, Jururu… Chupa, Juu…”

“Nuu♡ Fuun♡ Juju♡ Nn, Juzozozo…♡”

He drinks my saliva greedily, a young man consuming this shameful maid’s perverted fluids.

Recognizing this depravity, my lower abdomen burns.

(My womb… it’s hot…♡ Why am I aroused from my anus being pounded?♡)

My emotions are a mess. I can’t let this drive me crazy. I open my mouth to stop it—

“Uaa… Miyabi-san, sorry! U…!”

“Hae? Aaa, tsu…♡”

Suddenly, he cums inside my anus, his hot seed flooding in like a geyser.

(The same seed as the Saionji heir… in my anus…♡)

What a blasphemous, depraved act. Accepting the same genes as my future master in my excretory hole.

It’s unforgivable, yet it’s what he desires.

(Aa… so happy♡)

“Miyabi-san! I love you! I love you too!!”

(I love you too… so much. But…)

“I’m… a maid…”

I can’t say it. He must grow to be worthy of Ayaka-sama and the Saionji family.

“I’ll become a man worthy of you, Miyabi-san!!”

“~~~♡♡♡”

No, he must become worthy of Ayaka-sama. But I can’t say it.

(I’m so happy… so happy… How could I not be, when he’s striving for me?)

“Studies, sports, sex—I’ll work like my life depends on it.”

“Yes…♡”

He embraces me.

…

Hours later—

“U… aa…♡ A… e…♡”

I’ve taken all his desires, but at a cost—my mind and body are overwhelmed with pleasure.

“Thank you, Miyabi-san. How was anal sex?”

“It… was quite… overwhelming…”

Beyond skillful. If Ayaka-sama experiences this, she might indulge too. But a promise is a promise.

“So, anal with Ayaka-san… is okay?”

“…Yes.”

My petty interference was futile.

※

Since that day, I’ve added a new routine.

“Oh♡ Ooon♡ Ki, kkuuu…♡♡♡”

A custom dildo, perfectly replicating my master’s penis, now pierces my anus.

“Ayaka-sama… is doing this too…♡”

They’re likely in the bedroom, her anal virginity perhaps taken by his real penis.

“Ua♡ Aa… cumming, cumming~~~♡♡♡”

Imagining my beloved mistress and master sharing this pleasure envelops me in immense happiness.

“Everything changed since he came.”

The God Hand—a true genius gifted by the heavens, unlike a fraud like me.

(If I stopped contraception… I could bear his child.)

That might be nice. My child could serve the Saionji heir, their shared blood ensuring compatibility.

Then, I could dedicate my life to Ayaka-sama and my master.

(What a happy future…)

All thanks to him.

And so, tonight, I indulge in secret self-pleasure, feeling him in my anus.