How Using My Oppai Skill to Enlarge My Sister’s Breasts Led to Building a Harem - Chapter 45

Chapter 45

<Ai’s Perspective>

Three months since I left home, I’d settled into dorm life at Shinkou Girls’ Academy.

“Game, set!”

Reading my opponent’s return, my volley shot clinched the point, securing my spot as the only first-year regular on the tennis team.

“Amazing, Ai-san!♪”

“As expected of Lady Ai!♪”

Kanade-san and other first-year tennis club members cheered my victory.

(I thought elite tennis was about genteel rallies…)

I’d heard upper-class tennis was a social affair—hitting easy balls to foster conversation, not competition.

“To think it’s a real competitive team…”

“I lost. Never imagined yielding a regular spot to a first-year,” my opponent said.

“Thank you, Senpai.”

I bowed deeply to the senior I’d just defeated.

“Hehe, we don’t do that much here,” she said.

“Oh!”

My old track team habit had me bending 90 degrees—unladylike, against the “Be a lady” rule.

“Thank you for the thrilling match,” she said, offering an elegant curtsy.

(I’ve got a long way to go…)

Hadn’t I just been thinking winning wasn’t the point?

“Still, a first-year regular—how many years since the last?”

“Wasn’t it Amakawa-sama?”

“That’s right. For someone like Amakawa Miyabi-sama, it’s only natural.”

Hearing a familiar name, I interjected, “Is that the Miyabi-sama serving as a Saionji maid?”

“Oh, you know her?”

“Right, Ai-san was recommended by the Saionji family.”

Yes, Saionji Ayaka-san recommended me, and Miyabi-san taught me basic etiquette.

“Amakawa-sama is called the academy’s greatest prodigy.”

“She’s that remarkable?”

“Oh, yes. Her legends endure—each one unbelievable.”

Miyabi-san, my mentor, as a student? I was intrigued.

Always top in academics, undefeated in sports, she won nationals in tennis as a first-year. Poised, brilliant, strategic genius—seniors tossed around grand terms.

(Strategic genius feels out of place…)

What happened here?

“They say she stood by the beautiful princess, Saionji Ayaka-sama, like a knight.”

“How romantic! She yielded the student council presidency to Saionji-sama, a true vassal.”

(Ayaka-san was president…)

Her gentle charm captivates—Onii’s beloved.

The seniors’ tales continued, stories of a world far beyond my reach. Joining their excited chatter, I gazed toward the distant Saionji estate, feeling it was further than mere miles.

…

The sound of running water. Tiny warm droplets hit my skin, washing away sweat from intense practice.

(My tanned skin’s whitening, but these muscles won’t budge…)

In middle school, I was a sprinter, training rigorously, among the most muscular girls.

(Now, they’re just a hindrance…)

Sighing at my toned arms and faintly defined abs, I muttered, “Like this, Onii… Onii-sama will get taken…”

I thought of my beloved brother, raised together since childhood. Sometimes naughty, but kinder than anyone, always saving me when I’m in trouble. I—

“Nn♡ Aa… Getting wet…”

My fingers drifted to my shameful place.

Kuchi♡ Kuchu♡ Kuchu♡ Kuchu♡

Blending with the shower’s sound, I teased my core.

“Nnu♡ No… Can’t…♡”

I came here to become a lady, yet I’m lost in this unladylike act.

My naughty oppai, trained by Onii. The feminine pleasure his cock taught me.

They set my body ablaze.

Kuchu♡ Kuchu♡ Kuchu♡ Kuchu♡ — Bikun♡♡♡

“Aa♡ Aa♡ Aa♡ …Onii… Onii♡”

A light climax. Thinking of him, I masturbated in the dorm’s shared shower.

(I’m the worst…)

Wrestling self-loathing, I cleaned up and returned to my room.

Ping♪

“Hm… News?”

Grabbing my phone, rarely used now, I checked a fashion article. The headline stunned me.

“Sasahara Satsuki (16) Pregnant, Partner a Commoner Man—”

※

Humans struggle with firsts, especially a new life’s arrival.

“Contractions… started!”

“What!?”

As I prepared to leave the Saionji estate for home, Akane-san appeared, slightly frantic.

“—!? Is Ayaka-san in her room?”

“Yes… Please stay calm, Master.”

She was just as rattled. Knowing Miyabi-san was with Ayaka-san, I steadied myself.

“Can I see her?”

“Yes, I’ll guide you.”

Even familiar, I couldn’t dash through someone’s home. Following Akane-san’s brisk pace, I reached the bedroom.

Knock knock.

“I’ve brought Master.”

“You may enter,” Miyabi-san’s voice replied.

Hearing her, I turned the knob and pushed open the door.

“Excuse me. Ayaka-san!?”

“Ugh…”

Ayaka-san lay on the bed, groaning in pain, a stark contrast to her usual grace.

“Are you okay…?”

“I’m… fine. It’ll pass soon.”

“Calm down, Master,” Miyabi-san urged.

Right—contractions aren’t constant. They’d intensify, but birth could take over 12 hours. It’s a marathon.

“The hospital?”

“Already contacted. They’re preparing now.”

“I see…”

A Saionji-run hospital would receive her once ready.

(What can I do…?)

“Ayaka-san… Can I touch your belly?”

“Ugh… Hehe, of course. It’s… your child.”

“Yeah. Our baby’s… right here.”

“Nn…”

I placed my hand on her swollen belly, feeling our precious child.

“Aa… Darling♡ I’ll do my best…”

I’m not her husband—can’t be, perhaps. Society sees us as adulterers, our child forbidden. But that doesn’t matter now.

I’ll protect the woman and child I love. That’s more important than any law.

“Ayaka-san, I’ll keep touching…”

“Ah… Yes, please, Sensei.”

Sensei—a nostalgic name. Activating my hand’s ability, I continued.

“Nn♪… Feels good…”

I moved my hand gently, rubbing her belly.

(Pain relief alone should help, but… Hmm.)

The effect was weak—my power shines most when massaging oppai.

“Darling…”

Another contraction. Her face twisted, tears welling.

“I’ll ease it right away.”

I gently grasped her oppai, massaging softly funifuni.

(Careful, precise…)

Using all my knowledge, I pressed meridians safely.

“Aa…♡ Amazing…”

“How’s that?”

“Aa…♡ Strange…♡”

Pain relief required oppai stimulation, mixing pleasure and pain.

Praying to keep impure thoughts at bay, I massaged devoutly.

(Darling♡ I love you… Only you, forever.)

Her love, like a wedding vow, filled my heart. Overwhelmed with affection, my chest ached.

Pent-up emotions burst forth, unstoppable.

“I won’t let anyone take you or our child—”

“Aa… Aaa…♡ I want to be yours… Give you everything—”

The deeper our love, the more we’re tormented by what we can’t have. Painful, heart-wrenching. I couldn’t bear it alone.

“I love you.”

“I love you♡.”

Our words overlapped, sparking laughter.

Warmth filled me, sensing strength from Ayaka-san.

“How are you, my lady?” Miyabi-san asked.

“Fine, Miyabi. Contractions come, but they don’t hurt.”

“That’s good. Impressive, Master.”

She smiled faintly, bowing slightly.

“Haha, it’s my only talent.”

“An♡ Darling… Don’t knead my oppai… Ah!”

Pyuu~~~♡

Caught up in praise, I kneaded munimuni♡, and milk spurted from her nipples.

“Aa♡ Aa♡ Aa♡ No… Darling…♡ Miyabi’s watching!”

“S-Sorry.”

“Don’t mind me,” Miyabi-san said coolly.

If she’s unfazed, I’ll go all out.

“I’ll press pain-relief points for a while.”

“Nuu♡ Yes… Aa♡ My oppai… Leaking…!”

Pyu, pyuu~~~♡

I massaged gently to ease her pain.

“Aa♡ Aa♡ No… I’m cumming… Cumming…♡”

Her body responded perfectly to my fingers, as if under my control.

One final push.

(Protect my beloved and our child, Breast God.)

Focusing power in my fingertips, I pressed gunyu♡ into her oppai.

“A… Auuu~~~♡♡♡”

The effect was immediate—she reached a sweet, gentle climax, tension draining.

“Aa…♡ Feels good…♡ The pain’s fading…♡”

“I love you, Ayaka-san… Chu.”

Her swollen belly and leaking milk were truly beautiful. I kissed her cheek, holding her post-climax body gently.

“I’m not scared anymore…♡”

“I’ll always be with you.”

“Yes!♡”

I did everything I could for her. I planned to accompany her to the hospital, staying close until birth, but—

“That won’t do. You’re merely Ayaka-sama’s acquaintance,” Miyabi-san said.

“What…!?”

Reality was cruel. Claiming to be her husband at the hospital would cause a scandal.

Frustration surged, my fists clenching painfully.

(I can’t even be by my beloved’s side…?)

The powerlessness shook me. But Ayaka-san spoke, her face gentle.

“It’s okay, darling. I’ll be fine.”

“But I promised to stay…”

“Hehe, even apart, you’re… always with me.”

Her maternal smile was breathtakingly divine.

“Ayaka-san… Alright, I’ll stay here.”

“Yes♪”

We shared a final light kiss. Praying for a safe delivery, I let her go.

It was swift after that. Miyabi-san, silently observing, dressed Ayaka-san for travel, confirmed hospital readiness, and whisked her away by car.

Her efficiency left me stunned, only able to watch.

(Stay strong, Ayaka-san… I’m praying for you.)

Clasping my hands, I prayed to the gods—the only thing I could do.

※

“Couldn’t sleep a wink…”

“What’s that, husband? Sleep-deprived?”

“Rosecia…”

I ended up staying at the estate. It was a weekday, with school looming.

I wanted to skip, but lying in bed was pointless, so I dressed in my uniform and ate breakfast.

“Ayaka’s first birth is worrying, but you can’t let it weaken you,” Rosecia said.

“Haha, true. Miyabi-san’s there… It’ll be fine.”

“Hm, you hold Miyabi in high regard?”

“Duh, she’s one of a kind.”

I know it’s impossible, but I aspire to be like her—strong, cool, capable, kind.

“Kind? I wouldn’t know,” Rosecia said.

“That’s ‘cause you don’t know her.”

Her stoic face misleads people. She spends precious time guiding a mere student like me, showing me life’s path—a teacher, a master. Not respecting her would be absurd. I rattled off her virtues to Rosecia.

“You’re peculiar, husband…”

“…How?”

“Respecting women is odd.”

“Huh?”

I didn’t get it. Given her status and our talk, her claim that women aren’t respected baffled me.

“Few men in this world truly respect women.”

“No way.”

In medieval times, maybe, but today, most don’t belittle women.

“Gender equality, they say…” Rosecia began.

“Why do you think they started preaching equality?”

“‘Cause it’s better…”

I faltered, giving a vague answer—not a great one, it seemed.

“Hm, true, but a bit of a trick question,” she said.

“The answer—deep down, they’re steeped in misogyny.”

“…What does that mean?”

“Exactly that. They look down on women, so they chant equality as a performance to hide it.”

If equality were true, such chants wouldn’t be needed. That’s the logic.

“Know this? Women were made from a man’s rib, supposedly,” she chuckled.

“That’s…”

A famous story from a dominant monotheistic text.

“Children taught ‘woman came from man’—what do they grow up believing?”

“…What?”

I’m not a monotheist, so I don’t know. If Rosecia’s right, it sticks subconsciously, blocking true equality.

“You’re non-religious?”

“Pretty much. Normal in Japan.”

“But Shinto’s teachings linger at your core.”

“I’ve heard that.”

If we didn’t believe at all, temples and shrines wouldn’t exist. They’re woven into life.

“Even primitives worshipped gods. Every nation has religion.”

“Yup.”

“Back to it—your respect for women likely stems from that.”

“Does it?”

“Japan’s Shinto chief deity is a goddess, right?”

“Amaterasu Omikami.”

True, Japan’s highest god is female, formalized in the Meiji era.

“That’s rare globally.”

“Yeah.”

Zeus, Odin—male. A nation of 100 million with a female supreme deity is unique.

“That’s why Japanese men don’t resist truly respecting women.”

“Maybe so.”

I genuinely admire Miyabi-san, my mentor, and Rosecia, a queen ruling a nation.

“Kukuku, you’re adorable♪”

“Whoa, what’s that for?”

She pulled my head into her ample chest.

“Nothing. Just felt like it.”

“Got it…”

Sinking into her soft breasts, hearing her heartbeat, I relaxed.

(Feels good…)

My tense body, rigid with helplessness, unwound.

“Phew… Thanks, Rosecia. I’m recharged!”

“Good, good. Come back whenever you need this.”

Her fulfilled, gentle smile gave me a slight flutter.

(I’ll focus on what I can do.)

Energized, I headed to school.

I attended as usual, studying hard. At lunch, a message—“Delivery complete. Healthy boy”—eased my heart.