How Using My Oppai Skill to Enlarge My Sister’s Breasts Led to Building a Harem - Chapter 17

Chapter 17

Since being invited to the Saionji mansion, my life has gotten tougher.

On days without clinic duties, I study or train at the Saionji estate.

“First, studies—languages, politics, economics. I’ll teach you directly.”

My teacher is Miyabi, the Saionji family maid.

“We’ll use dialogue for efficient learning.”

It’s about episodic memory. Memorizing raw data is hard for the brain, but unique experiences stick. Miyabi teaches masterfully, adjusting to my level, making it highly effective. Plus—

“That part was tricky, wasn’t it?”

“How’d you know I didn’t get it?”

“I’m a maid. Failing to read my master’s face would disqualify me.”

Her knack for reading expressions auto-adjusts difficulty.

(She’d be a top-tier teacher…)

Studying under her, I never imagined I’d soon top my school’s grades.

…

“Next, training. We’ll use the mansion’s gym.”

“Y-Yes.”

“Bodyweight exercises like squats and pull-ups are good, but specialized equipment is more efficient.”

Miyabi, in sportswear, guides my physical training with gym-trainer-level expertise.

“Haa… haa… my arms won’t move…”

“That’s enough. Have this drink.”

She hands me a milky, viscous beverage.

“A protein shake developed by a Saionji group company for pro athletes.”

“Nn… gulp… Surprisingly tasty.”

“It’s tailored to your genetic profile, excluding incompatible ingredients.”

It contains essential proteins, vitamins, minerals, amino acids, and cutting-edge supplements, customized for the individual—apparently the future standard.

“Human athletic ability is genetically determined.”

“Really?”

“Science proves that at the top level, effort can’t bridge genetic gaps.”

She cites sprinting: those with long-distance muscle genes rarely compete in Olympic sprints. Training in your genetically suited field maximizes potential.

“I’ll guide your training based on data.”

“Y-Yes, please.”

Sipping the custom drink, I listen to her lecture. In a sports bra and leggings, Miyabi’s more exposed than in her maid outfit, exuding a different allure. Staring at her—

(My body’s getting hot…)

My crotch stirs. Thinking it’s post-workout arousal, I try to calm it, but focusing only makes it worse.

“Master, while impressive, that might hinder training.”

“S-Sorry…”

“Just say the word, and I’ll calm it down.”

“Huh…?”

Miyabi approaches my bulging cock and lifts her sports bra.

Purun♡

Her breasts spring free, bouncing up and down.

“Wow… incredible…”

“M-Master, my breasts aren’t anything to praise…”

“No way!”

“! …But my areolas are so large, it’s embarrassing.”

Her nipples are indeed larger and thicker, but that’s part of their beauty.

“They’re gorgeous. No need to be ashamed.”

Unconsciously, I start kneading her ample breasts.

Nyu♡ Gunyu♡ Munyuu♡

“—…Ah♡”

My fingers hit a sensitive spot, making her tremble like she’s been struck by lightning, then freeze.

(It’s working… Pleasure’s spreading from her breasts’ nerves.)

My newfound skill lets me sense her sexual pleasure clearly.

“Feeling it, Miyabi-san?”

“N-No… I’m… not feeling… anything…”

“Then I’ll keep going.”

“S-Such… ah, u…♡”

Guniguni♡ Munyumunyu♡ — Gyu♡♡

“Hao…♡ Ngi… Iii♡♡♡”

Incredible. The pleasure she’s feeling would knock out most people. Her restraint, with only moans escaping, shows her immense willpower.

“Rotating like this… eases shoulder stiffness, right?”

“Nn! T-That’s… enough… please… au♡”

Her legs shake, nearly collapsing.

“Whoa!”

I catch her, preventing a fall.

“S-Sorry, master…”

“No, I overdid it.”

This isn’t meant to be done standing. My fault.

Still, seeing the sharp, genius Miyabi slurring her words is… cute.

(And… she smells good. Women’s sweat is this sweet?)

Her sweat, mixed with feminine pheromones, smells sweet to me.

“Oh… crap…”

My balls churn with boiling semen, my cock rock-hard, ready to burst.

“Huh? Oh, right… ahem. Master, it’s my turn to serve.”

“Haa… haa… please.”

“Fuu… Excuse me.”

Miyabi bows to my crotch, hooks her fingers in my sportswear, and slowly pulls it down.

“Ah… What a splendid manhood…”

My cock, aroused by her allure, throbs with bulging veins.

Sniff sniff… “Haa…♡ The scent of a young man… —Sorry.”

She breathes rapidly, inhaling my cock’s smell.

The air around us is thick with my sweaty crotch and her pheromones.

“The taste… rero♡ Sweat and… a hint of urine…”

“M-Miyabi-san…?”

“Leave it to me, master. I’ve trained for years for this… Nn, juppo♡”

“Uah…!”

Her lush lips engulf my glans.

Jururu♡ “Nn, nn, nn♡ Rero… Chururu, Zuzuzu♡”

“Ugh… aa… my tip’s melting…”

“Nfufu♪ Feels good, master? Juzuzu♡”

“Too good…!”

Her first blowjob, yet her superhuman learning and dildo training make her a pro.

Haamu♡… “Juzu! Nn♡ Nn♡ Nn♡ Nnnu♡”

She bobs her head, gazing up at me. A peerless beauty with unmatched intellect, sucking my cock… It’s thrilling, and I sense genuine respect from her.

“Aa… Miyabi-san, I can’t take it…”

I instinctively stroke her silky hair.

“Nfu♪ Then, here I go… Ah~ Nn♡”

She takes my cock deeper, opening her throat, slurping it down. The slick sensation, tight throat, and surreal feeling of being devoured by a beauty make my cock swell.

“Nn! Go…! Ogo… Go!!”

Her airway blocked, her throat writhes to expel the intrusion.

“Gu… Ogo! …Juzuzu”

Still, she doesn’t stop serving me. My hand senses some of her pain.

“Miyabi-san, don’t push yourself. That’s enough.”

“!? —Jururu♡ Jupu, Jujuju♡ Ogo…!!”

Her maid’s pride refuses to release my cock, trying to take it deeper.

“Gu… U, uuu…”

“Miyabi-san! Spit it out!”

My hand feels her agony, but she clings to my cock, even near fainting.

(Her pride’s too strong… Normal words won’t work…)

“Miyabi-san, it’s an order. Spit it out.”

“N!? (Nod) Gaha…! —Cough, cough…”

She was in real pain, tears in her eyes, choking back sobs.

“Miyabi-san, I love that you want to please me, but don’t hurt yourself.”

“I’m not…”

“You are. I don’t want to feel good at your expense.”

“…”

My hand senses pleasure—and pain.

“Your effort makes me happy.”

“Master…”

I stroke her head with all my affection.

(Won’t she hate me for this…?)

I don’t look down on her—I respect her. But she’s hurting, guilty for failing her duty. I want to ease that.

“I’m happier if you feel good too, Miyabi-san.”

“Yes… I understand, master…”

I keep stroking her head.

She squints happily, looking up at me.

(She’s so cute… How’s an adult woman this adorable?)

My heart pounds staring at her.

“Then, I’ll serve you within my limits. Nhaa… Ammu♡ Juu♡”

“Nn… aa… good, Miyabi-san…”

She takes my glans again, stopping short of her throat, sucking eagerly.

Juu♡ Jurorororo♡… “Nn♡ Nn♡ Nn♡”

“Ua! That’s amazing…”

“~~~♡ — Nju♡ Juu♡ Juu♡… Juzuzuzu♡”

Incredible. With only half my cock in, her dedication fills my heart.

My hand, stroking her head, senses she’s feeling pleasure.

(She’s feeling it… while sucking my cock…)

Her mind seems flooded with pleasurable fluid. Her pupils dilate, her body twitching with joy.

“Miyabi-san, are you coming?”

“!? …N-No, I’m not…!”

But each stroke of her head makes her body quiver, like a dry orgasm, climaxing without touching erogenous zones.

Jurororo♡ Rero reroro♡ “Nn, nn, nn♡♡♡”

“Kua…! That’s too good…”

I almost pull back, but she grips my cock’s base, continuing her blowjob.

“Aa… If you do that, I’ll fall for you, Miyabi-san…”

“N!? ~~~♡♡♡ Juu♡ Jururururu! Juu♡ Jupo♡ Jupo♡♡♡”

“No…! Aa, my cock’s melting…”

Falling for a woman sucking my cock? Pathetic, like I’m thinking with my dick.

But how could I not? A beautiful, amazing woman sucking me so earnestly—I’d be crazy not to love her.

Jubobo♡ Jururu… Rero rero rero♡

“Aa… I love you! I love you, Miyabi-san!!”

“♡”

Each “I love you” makes pleasurable fluid burst in her mind, my hand feeling it. I stupidly repeat it.

“Hao♡ Master♡ I… …”

Her face red, she tries to say something, but—

“No! I’m cumming!!!”

“Nn~~~♡♡♡”

My cock can’t hold back.

Dopyu♡ Byurubyururu♡

“Ngu♡ …Nhaa, jururu♡ Nku♡ Nku♡”

“Don’t force yourself to swallow…”

The sudden, massive load overwhelms her, semen dripping from her mouth as she gulps it down.

“Nn♡ Juu♡ Nku♡ Juuu♡… Gokun♡ — Chupo♡”

She swallows it all.

“I spilled a little…”

“It’s fine… That was amazing.”

She licks the semen dripping to the base. Seeing her, I’m utterly satisfied.

“Truly satisfied?”

“Of course. Beyond words.”

My heart’s content. But my body, in extreme arousal, won’t soften—blood keeps rushing in.

“It’s… my body acting on its own…”

“I see… Then… Nn.”

Miyabi lies on a nearby mat, strips off her leggings, and—

“Use this hole as much as you like.”

—she spreads her legs, opening her pussy wide.