The next morning the mansion smelled like vanilla and sin before Katsuki even opened his eyes.

He came downstairs in nothing but low-slung black boxer briefs, cock already half-hard from another night of blue-balled torture, and froze at the kitchen doorway.

Izuku was at the stove making pancakes.

Wearing nothing but one of Mina’s oversized sleep shirts — the one that barely reached the bottom of her fat ass cheeks. No panties. Nothing. Just smooth white thighs, that perfect peach of an ass, and every time she shifted her weight he could see the glistening pink lips of her pussy peeking out, already wet.

She hummed happily, flipping a pancake, then “accidentally” dropped the spoon.

“Oh nooo~” she sang, bending at the waist, legs straight, ass popping up like an offering.

Katsuki’s breath punched out of him.

Her pussy was right there — fat, puffy, slick-shiny in the morning light, clit swollen like a little pink pearl, a thin string of her arousal already dripping down her inner thigh. She wiggled her hips just once, slow and deliberate, letting him see everything.

Mina sat at the breakfast table, sipping herbal tea, belly round under her robe, smiling like an angel.

“Izuku is such a good helper in the kitchen!” she chirped. “Look at her go!”

Katsuki nodded so hard his neck cracked. His eyes never left Izuku’s dripping cunt.

“Yeah,” he growled, voice wrecked. “Real… helpful.”

Izuku straightened up slowly, turning with the most innocent smile, spoon in her mouth like she was sucking cock.

“Morning, kacchan~ Did you sleep well?”

She let her eyes drop to the massive tent in his boxers, licked the spoon clean, and bit her lip.

Katsuki wanted to bend her over the counter and fuck her until she screamed. Instead he muttered, “Fine,” and sat down fast, thighs clenched so his cock wouldn’t throb visibly.

The days blurred into pure torture.

Izuku never wore more than scraps. Tiny crop tops that let her underboob spill out. Daisy dukes cut so high her ass cheeks hung out. Sheer baby-doll nighties with no panties underneath. She’d “forget” to close the bathroom door while she lotioned her massive tits, moaning softly like she was fingering herself. She’d stretch in the living room, back arched, shirt riding up to show the bottom curve of her bare pussy while Mina cooed about how flexible her little sister was.

Every night Katsuki jerked off in the shower until his dick was raw, biting his forearm to stay quiet, imagining pounding that fat pink cunt until she cried.

Mina remained blissfully clueless.

“My baby sister is the sweetest,” she’d say, rubbing her belly. “I’m so lucky.”

Katsuki was losing his fucking mind.

Then came the night around 2 a.m.

He couldn’t sleep. Cock so hard it hurt, balls heavy and aching. He crept downstairs for water — or maybe just to punch something — and stopped dead in the kitchen doorway.

Izuku was bent over, head and shoulders deep inside the open fridge, ass completely out. She wore only a tiny white tank top that had ridden up to her waist. No bottoms. Legs spread. Her fat pussy lips were swollen and glistening, a drop of wetness sliding down her thigh.

She heard him. Turned her head, ice cream carton in one hand, spoon in the other, and gave him the filthiest little smirk.

“Couldn’t sleep either, kacchan?” she purred.

Then she scooped a huge spoonful of chocolate ice cream, wrapped her full pink lips around it like it was the thickest cock she’d ever seen, and sucked hard. Her cheeks hollowed. She moaned, eyes locked on his, tongue swirling obscenely.

“Mmmph… so thick and creamy…” she mumbled around the spoon, letting a little melt drip down her chin onto her tits.

She pulled the spoon out slowly, strings of saliva and melted ice cream connecting her lips to it. Then she licked her fingers one by one — long, wet, sloppy licks — staring straight at the bulge in his sweatpants.

Katsuki groaned out loud, deep and broken. His cock jerked hard enough to tent his pants obscenely.

“Jesus fucking Christ, Izuku…”

She giggled, low and dirty.

“What? I’m just having a midnight snack. Want some?” She dragged her ice-cream-coated finger between her tits, then sucked it clean again. “It’s so messy… I always make a mess when I eat something big.”

He thought, She is such a fucking slut. And I want to ruin her.

He turned and walked out before he did something irreversible.

A few days later Izuku came downstairs pouting, rubbing her shoulder.

“Sis, my shoulders are killing me from all the helping…”

Mina instantly looked guilty. “Oh no, my poor baby! Katsuki, honey, can you give Izuku a massage? You’re so good with your hands.”

Izuku’s eyes sparkled. “Pretty please, kacchan~?”

Katsuki’s jaw flexed. “Sure.”

Upstairs in the guest room, Izuku had already stripped. She lay face-down on the bed in nothing but a tiny black thong that disappeared between her massive ass cheeks. Topless. Her huge tits squished out to the sides, nipples hard against the sheets. Her ass was oiled and shining, hips slightly raised like she was presenting herself.

Katsuki’s cock went diamond-hard instantly.

“Izuku…”

She looked over her shoulder, all big innocent eyes and pouty lips.

“It’s okay, kacchan. Just my shoulders… unless you want to do more~”

He sat on the edge of the bed, hands shaking as he placed them on her smooth shoulders. The second he touched her she let out a p*rn-star moan — long, breathy, filthy.

“Fuuuuck… your hands feel so good, kacchan… harder… mmm yes, just like that…”

It sounded exactly like she was getting fucked.

He worked down her back, thumbs digging into her spine, and she arched like a cat in heat, pushing her ass up higher. His fingers brushed the sides of her massive tits — soft, warm, spilling out under his palms. He could feel her hard nipples grazing his knuckles.

“Lower, kacchan… please… my back is so tight…”

He slid his hands down, dangerously close to her ass. She wiggled — slow, deliberate, rolling her hips so her fat cheeks jiggled and her thong string pulled tighter against her soaked pussy.

Katsuki’s control snapped. He pinched one perfect ass cheek hard.

“Awww~” she whimpered, but her voice was dripping with lust. “Kacchan, that hurt…”

“You were wiggling your slutty little ass right in my face,” he growled, voice low and dangerous. “What did you expect?”

Inside his head he was screaming: I want to rip this thong off and spank you raw. I want to shove my cock so deep in that dripping cunt you forget your own name. I want to breed you while your sister sleeps downstairs.

Izuku just moaned again, pushing back against his hand.

“Maybe I like when you’re rough with me, kacchan…”

His phone buzzed beside him. Mina calling.

He snatched it up, voice hoarse. “Yeah, babe?”

Izuku smirked into the pillow, reached back, and slowly dragged two fingers through her own soaked pussy, then brought them to her mouth and sucked them clean while staring at him.

Katsuki hung up fast.

“Mina needs me.”

He stood up, cock straining so hard it hurt, and walked out without another word.

Behind him, Izuku rolled onto her back, legs spread wide, fingers already circling her swollen clit. She was dripping onto the sheets.

“Poor frustrated kacchan,” she whispered to the empty room, smiling like the devil. “You’re gonna break soon… and I can’t wait.”