Don't Pull Out! The TA's Right Outside!
"Really! You say anything to your sister, seriously!"
[Seo-ah's Perspective]
"Ptoo!!" I spat out the towel in a flash.
Grab! I slammed my upper body flat against the floor. My legs whipped back, clamping down on Seojun's thigh as he tried to escape like a lifeline. Then I bucked my ass up ferociously toward his pelvis.
Squiiiish!!
"...! S-Sis?!"
The glans that had been slipping out got rammed deep back into my pussy. A heavy thunk right against my cervix. Finally, I could breathe.
I whipped my saliva- and tear-streaked face around. Gnashing my teeth, I glared daggers at Seojun.
"You crazy fuck. Where do you think you're pulling out to."
"There are people outside! What if we get caught?!"
"I don't give a shit if that TA shows up or not?!"
What did I look like in Seojun's eyes? I wanted to be the kind, gentle big sister. But I knew better. I was just a beast in heat, nothing more.
Pathetic. But even so...
"Can't you see my pussy twitching for your cum?! Shut up and slam it in to the end!!"
A snarling threat. Cheap, shameless begging after tossing aside any pretense of dignity. The hunger terrified me far more than the humiliation.
Seojun's startled eyes widened. Then resignation washed over his face. My sweet, foolish little brother gripped my hips tight and nodded.
"Professor? Are you not in? It says you're in your office..."
The TA's voice rang out again. I had to answer.
Snap. I flicked my fingers, weakening the soundproofing spell just a bit.
"Hah, ahem! C-Cough... T-Teaching assistant."
I glared at the empty air, squeezing out my voice. As calm and rational a professor tone as I could manage.
"I'm in the middle of... something important... right now... Nngh!"
That was when it happened. Squelch... grind... schlick.
"...?!"
Seojun pressed tight against my back. The bastard started slyly rolling his hips in circles. Piston thrusts that ground into every single wrinkle of my inner walls. Bliss crushing my swollen sensitive spots without mercy.
This crazy fuck really...!
My vision flashed white. I told him not to pull out—not to torture me like this.
There's someone... right outside the door...!
My hole quivered and clenched. My womb churned and spasmed. The thrill of taboo crushed the pleasure switch flat.
"P-Professor? Your breathing sounds off. Are you unwell? Should I call someone?"
Panic crept into the TA's voice. My fingers turned white, clawing into the sofa cushion.
"N-No... just mana circulation is a bit... Nngh...! Hah..."
I bit my lip until it bled. Barely stifling the moan about to burst out.
"I'm focusing on mana circulation... Nngh?! And using up... some stamina!"
Churn! Churn! Squelch! From our joined gap, frothy white bubbles spewed endlessly.
"So the paperwork, hng...! Just... slide it under the door!"
I finally forced out the words in my trembling voice.
"Ah... yes. Got it. I'll slide it under the door."
Shh. An envelope slid through the door crack.
"Please sign it when you can, Professor. Rest up."
Thud. Thud. The footsteps started fading away.
================================
[Seojun's Perspective]
The footsteps receding.
"...Hoo."
I exhaled the breath I'd been holding. Behind Sis's back. While she answered in her usual steady voice...
Her pussy walls kept expanding and contracting without pause.
She's so fucking hot right now.
Excitement overpowered the fear. The moment the footsteps vanished completely...
The tension released, and her body hit its limit.
"Aaaaaahhh-!!!"
She clawed the sofa, convulsing wildly. Spluuurt-!!
"S-Sis?!"
A pale yellow stream gushed down her creamy thighs. The sharp tang of urine mixed with sweetness, dripping onto the floor.
"Dick! Diiiick! Seojun, cum quick! Fill me up insiiiide...!"
Her eyes rolled back in a whore's frenzy. Oblivious to her own mess, she thrashed her hips back madly.
I was at my limit too. Blood surged to my lower half like it might burst.
"G-Gonna cum...!"
I gripped her hips and thrust long and deep. Thud. Hit her cervix. Crushed it mercilessly and unleashed.
Splurt! Splurt! Spuuuurrrt...!!
"Kyaaaaahhh!!!"
The intensity matched how long we'd held back. Thick, dense male seed battered her womb walls, stuffing every empty space tight.
Churn. Pffft! Ziiing-!
"Ah, aaahh...! Uwa... it's coming in, so much... Nngh...!"
An insane volume that made her belly bulge. Her lower body spasmed wildly.
"Ah."
Then, a dazed sigh. Her upper body flopped limp onto the sofa cushion.
"Haa... haa..."
I collapsed sweat-soaked onto her back. Our ragged breaths echoed trapped in the soundproof barrier.
As the convulsions finally ebbed...
"...Hey."
Seo-ah, rubbing her cheek against the sofa. She wiped away the caked tears and snot, opening her mouth.
Back to my normal sister.
"What."
"Don't pull out... stay a bit longer."
Her red mucosa still gripped me firm. The folds wriggled nonstop, lovingly lapping at my shaft.
Why was it? This sensation of her wrinkles caressing my length. It strangely resembled the warmth of her hand stroking me when our parents died.
A fuzzy warmth bloomed in my chest. Back then it was her hand. Now it was her pussy—but the feeling was the same.
"And tomorrow."
"Yeah. What now."
Sis twisted her head slightly, shooting me a glare. She'd soaked the leather sofa in her own fluids. Her belly sloshed with her little brother's cum.
Yet her tone was brazen as ever.
"Wake up earlier tomorrow morning. Cum twice before you go."
I snorted in disbelief.
"Regulate your absorption yourself. Don't cling before afternoon classes even end. I'll turn into a mummy at this rate."
"Idiot. How am I supposed to control that? If anything, your cum dries too fast. It's all watery. No wonder you're a premature shooter."
"Who's fault is it your pussy's possessed? Speaking of, you've gained weight lately, huh?"
"...How do you know that?"
"Linked the scale app. Change your smartphone passcode to something harder."
"You little shiiiit...!"
The usual sibling bickering flew back and forth. Sis's cheeks flushed beet red.
"Really! You say anything to your sister, seriously!"
An indignant voice. But her insides reacted differently. Squelch. Schlick.
Still soft and warm, wriggling pleasurably. An itchy, heart-melting stimulation.
We kept sniping at each other up top. Well, this was sibling love too, right?
================================
How much time passed like that? We couldn't just lie there forever. I had classes too.
And crucially, it felt like she might squeeze me dry.
Time to pull out.
"Gonna get up now."
I carefully tensed my abs and drew my hips back.
"Nooo..."
Suddenly, her pale legs hooked my ass tight.
Grabbing me from behind while lying down? Impressive flexibility, Sis.
She twisted her waist, whining.
"Don't pull outtt... stay like this a bit longer..."
"No can do. Gotta wipe and get dressed. Don't you have afternoon lectures?"
"Just a liiiittle... I wanna suck more of Seojun's out of youuu..."
Total spoiled brat mode. But my stamina was tapped out.
"We'll do more at home. Pulling out now?"
I pried her thighs loose and slowly withdrew.
Shhh-. Squelch! Squiiiish-!
"Ngh...!"
Every inch out, her tight mucosa resisted fiercely. The demonic folds clamped my glans, refusing to let go. Her entrance sucked like it might come with me.
And then. Pop! Pffft!!
I broke free from the clinging grip at last.
=========================
[Seo-ah's Perspective]
"Ah..."
Deep in my belly. An aching emptiness.
At the same time, my inner walls, springing back without friction, contracted sharply.
Ziiing-!!
The tip scraped my entrance on the way out. Brain-melting pleasure slammed my spine.
"Ohhk...?!"
A crude moan slipped out unbidden. Shiver shiver shiver!
"Aaah...! Ohhuuuk?!!"
My whole body went rigid, flopping like a live fish. My toes curled grotesquely.
Splat! Glorp, churn! Squelch!
The red gash I couldn't close. The empty hole twitched wildly, vomiting up white globs nonstop.
The black leather sofa. Slick fluids, fresh piss, backflowing juices—all mixed in a filthy mess.
"Haa... haa..."
Eyes half-lidded, my hips quivered. Drool and towel lint crusted my lips uncleaned.
As I flailed in the afterglow, panting...
A ridiculous chuckle rained down from above.
=========================
[Seojun's Perspective]
"Pfft...!"
I burst out laughing at the absurdity.
"'Ohhk'? What's that, 'ohhk'? This isn't some Japanese porn!"
"Huu... Wh-what...!"
Her wine-red eyes refocused at the mocking words.
"You were all 'Professor' mode with the TA there. But your moans are 'ohhk'?"
"Wh-when did I...! And I am a real professor!"
Her cheeks burned crimson. But drained of strength, she couldn't even sit up. Face-planted into the sofa cushion. Her silver hair parted, revealing ears red-hot.
"Wh-who said 'ohhk'... You're lying, seriously...!"
A pitiful shred of pride in her whine. Adorably insane.
"Yeah yeah, Sis. Get up for now. Lemme wipe you down."
"Hiiing... Nooo... It's all empty now, feels so hollow..."
"Gotta wipe. It'll be harder once it dries."
I knelt, yanking out a wad of wet wipes. Carefully dabbed the puddle between sofa and thighs.
Swish. Shhh.
"Hngt! Hey... wipe gentler..."
"I'm being gentle."
Her puffy crotch. The spot that had devoured me and gone wild moments ago. Churn. Ziiing-
Traces of me pooled thick in the red slit. Leftover desire frothed out.
"But Sis."
I tossed it out casually while wiping her inner thigh.
"You almost screamed back there. That was really close. What if the TA figured it out?"
"...!"
Sis jerked her head up.
"Hey!!"
"What."
"Your fault?! You crazy bastard, there's someone at the door and you poke my G-spot?!"
She shrieked. Righteous fury exploding.
"You were totally trying to kill me! I nearly had a heart attack!!"
"You wouldn't let go of my thigh. I panicked and my back gave out."
Ridiculous. She latched on first, now blaming me?
"Still! I'm dying of nerves and you thrust there?! You pervert!"
"If anything, you swallowed me first. Who's the pervert? And honestly..."
I chucked the wipe in the trash and grinned.
"You squeezed harder every time the TA spoke."
"Y-you little...!"
Her flushed face boiled over. No comeback, just lip-biting and trembling.
"Whatever! There's spare clothes in the cabinet over there? Get 'em."
"Yes ma'am."
Even now, bossing me around. I rummaged the cabinet for backups.
But...
"No panties...?"
"Forgot..."