While Taking Care of My Shut-In Little Sister, I Somehow Ended Up Ejaculating Inside a Beautiful Girl

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Chapter 85: Side Story: Teacher and Student Are Living Together! ~Even Teachers Need a Break~

“Sensei. Sensei.”

“…”

The sweet whisper in his ear didn’t rouse the man.

For a thirty-something body, a long weekend is a precious chance to recover from a week’s exhaustion.

The man is a teacher.

Though working conditions have slightly improved recently, the workload of a “school’s jack-of-all-trades”—guiding students, teaching classes, handling paperwork, and tackling miscellaneous tasks—remains overwhelming.

With early mornings and evenings that stretch close to night, he might work as long as a small business CEO despite being just a regular teacher.

So, long weekends are invaluable.

This three-day weekend, and the looming Golden Week, are times when even a teacher wants to let loose like a student.

Teachers need breaks too.

…And yet.

“Sensei. Sensei.”

Even in his dreams, he hears a student’s voice.

A voice calling “Sensei, Sensei.”

What a great teacher he’d be if he could smile and respond kindly despite his tired body.

That’s the kind of teacher he admires.

But he knows he’s not that person.

He’s too aware that his exhaustion shows in his face and words.

Still, he’s grown. Physically, maybe not, but mentally, he’s tougher.

He’s learned to pace himself, to find efficient ways to catch a breather, and to handle his work smoothly.

…So, on a long weekend, at least.

On a break, he just wants to rest.

“Sensei, wake up.”

A student’s voice tries to pull him from blissful sleep.

Even in his dream, forcing him to “wake up” feels like work—an unfair demand that angers him with irrational resentment.

…He just wanted to rest.

To be left alone.

“—O-nii-chan.”

Huh, the man thinks.

Only one person calls him that.

The repeated “Sensei” calls had already stirred a work-like tension in his hazy dream, as if he were at school.

Then.

“Onii-chan.”

A voice calling him that way.

A name he’d never allow at school.

A forbidden word.

“Onii-chan.”

…Yes.

A name that could socially destroy him.

A threat to his stable life.

A call that, if heard publicly, would almost certainly end him.

“Onii-chan.”

The nightmare repeats in that sweet voice.

“Onii-chan.”

Again and again, beckoning him to ruin.

“Onii-chan.”

“—!!”

The voice shifts his dreamscape to a school hallway, the call coming from behind him—outside his field of vision.

He turns around—

“Dinner? A bath? Or… me?”

Before him stands a female student—a bespectacled beauty he’s living with.

“—…Uwoooaaaahhh!”

The man screams in a half-crazed panic.

Not just a scream, but a low, guttural, horrifying wail—a desperate, primal cry an adult man might let out when facing death.

“Onii-chan, you’re awake?”

“Don’t call me that at school—! …Wait…?”

His blurry vision sharpens, focusing on the room’s ceiling.

“Haa… haa…”

Calming his breathing, he notices a beautiful girl peering at him from the edge of his vision.

What the hell, I’m at home? And it’s her, the real her, but waking up to this is brutal, he thinks, a flood of reactions swirling in his mind.

“Good morning, Onii-chan.”

The bespectacled beauty smiles brightly, her twin braids hanging from the back of her head.

Her sharp gaze softens her gentle features, giving her an intelligent look. And she is smart—one of the top students in a competitive school of about 300. Her quiz results alone suggest she’s near the top.

“Nice way to wake up, huh?”

“The worst… I thought I died…”

“Overreacting to ‘Onii-chan’? You don’t have to be that happy.”

“I dreamt you called me that at school. Dream-me is definitely socially dead… Thanks for that…”

“I’ll take care of you if that happens.”

“Damn… Revenge gets me nothing… Vengeance breeds nothing…”

Tossing in some cheesy, movie-like lines, he groggily drags himself out of bed, trying to shake off the fog.

“Breakfast is ready.”

“Thanks, I owe you…”

The girl—Koharu Iida—prepared a traditional breakfast of rice, miso soup, and three side dishes.

Looking at the simple but appreciated meal, the man mumbles his thanks, still dazed.

“This three-day weekend, you’ve got nothing planned… That’s just too much, Onii-chan.”

“!?”

Koharu, sitting across from him at point-blank range, her eyes narrowed with a wistful look, throws him into confusion.

He’d planned to pick up his suits from the dry cleaner in the morning, do some shopping for daily necessities, eat lunch, and relax at home in the afternoon.

So why—

“Mmph!? Mmph!! Mmmph!?”

“No choice. It’s just how it is, Onii-chan.”

Gagged and bound, the man can’t move or speak properly—

“—Ngh. Come on… I’m your fiancée! You could want me more! It’s your fault, Onii-chan, treating me like a kid just because you’re older… Even during sex, you always hold back…! —Ngh, ah, haa… ahh!”

Slap, slap, slap… The wet sounds echo in the room.

On the man’s lap, the girl bounces, slamming her hips down.

Her breasts jiggle in front of his eyes.

In their apartment, he leans back on the sofa.

His lower half is already bare, her hot vagina rubbing against his penis.

From their joined parts, a mix of her fluids and his precum bubbles white.

“Ngh! Mmph! Mmmph!!”

“It’s okay, Onii-chan, just relax. You’ll feel good soon. Forget the neighbors.”

“Mmph!? Mmmph!! Mmmph!!”

After breakfast, he’d felt sleepy for some reason, and woke up like this.

“Look… I’m already this wet…”

“…!?”

Koharu points to her dripping vagina, then slides her finger to her abdomen, where her womb lies.

Her body is in transition to adulthood. Still youthful as a high schooler, yet undeniably maturing into a woman—a perverse, alluring figure.

To the man, who remembers her as a child, her grown hips, breasts, and toned abdomen stand in stark contrast.

“Onii-chan, play with me~!”

That memory, unwillingly, sends a jolt of pleasure through his hips.

“Onii-chan, you have to marry me when we grow up, okay? Promise!”

Time has passed, but the age gap remains.

Despite the difference in age and size, her approach to adulthood, her ability to reproduce, her strong desire for it—

It creates a sliver of weakness in him, a gap.

She wanted this—he didn’t initiate it—

Such convenient, self-indulgent thoughts flicker in and out.

They chip away at his rationality, snuffing out any chance of restraint.

Morals, appearances, teacher-student boundaries, adult-child distinctions—they all fade. The pleasure, the raw desire to be a foolish male, is too overwhelming.

“—Ngh! Onii-chan, Onii-chan… ahh! Ngh—! Onii-chan—!”

Her heat radiates as she frantically moves her hips. He feels blood rushing to his groin, her heat consuming his mind.

They’ve done this many times, and each time, her vagina feels incredible.

Their physical compatibility strips away his will to resist.

“Nnngh—! Nnngh! Nnngh!!”

“Forget everything today, just melt into me! Give yourself to me!!”

“Nnngh! Nnngh!”

His last shred of resistance is futile. His attempts at meaningful words turn to meaningless sounds, which she takes as moans, spurring her to thrust harder.

“Nnngh! Nnnngh!!”

“So good! So good, Onii-chan! Your cock feels so good! I’m gonna come! I was holding back, but I’m gonna come! So—Onii-chan, you too—!”

Whether those were moans or not no longer matters.

She’s deaf to him, focused only on milking semen from his penis and scrotum.

Her vaginal walls stroke his shaft, glistening with slick fluids and white foam.

Each withdrawal stretches her flesh slightly, each thrust pushes it back with a joyful squish.

Over and over, repeatedly.

“Nngh!! Nnngh!!”

“You’re gonna come, right? It’s okay, come! Shoot it out!”

“Nnngh!! Nnnngh!!”

No, that’s not it—his words can’t form through the gag.

“I’m coming…! It’s happening, it’s okay, come! Fill me with your hot cum—!!”