Jake slammed the front door behind him and kicked off his boots. The house was quiet except for the low hum of the AC. He thought he was alone until he heard the shower running upstairs. His little sister Emma was supposed to be at work, but her car was in the driveway. He climbed the stairs two at a time, already half-hard from the heat outside and the thought of catching her off guard.
He pushed the bathroom door open. Emma stood naked in the middle of the room, towel forgotten on the floor, water still dripping from her hair. Her ass faced him, round and wet, the tight pink ring of her asshole visible between her cheeks. She spun around when she heard him, tits bouncing, nipples hard from the cool air.
"Fuck, Jake. You can't just walk in," she said, but she didn't cover herself. Her eyes dropped to the bulge in his jeans.
"You left the door open," he growled. He stepped closer, grabbed her wet hips, and spun her back around. "Bend over the counter."
Emma hesitated for half a second, then leaned forward, pushing her ass out. Jake dropped his jeans and freed his thick cock. He spit on his hand, rubbed it over her asshole, and pressed the head against it.
"Been thinking about this all week," he said. He pushed forward, stretching her tight ring. Emma moaned, low and dirty, as his cock sank into her asshole inch by inch. Her ass gripped him hot and snug. He didn't stop until his balls rested against her pussy.
"Fuck, big brother, you're so deep in my asshole," she panted. Jake pulled back and slammed in again, setting a hard rhythm. The wet slap of skin filled the room. He reached around and rubbed her clit while he fucked her ass, feeling her get wetter on his fingers.
Emma pushed back to meet every thrust. "Harder. Wreck my asshole, Jake. It's yours."
He gripped her hips tighter and pounded faster, watching his cock disappear between her cheeks. Her asshole stretched around his shaft, shiny with spit and precum. He slapped one cheek, then the other, leaving red handprints. Emma's moans got louder, turning into short gasps every time he bottomed out.
Jake pulled out, spun her around, and lifted her onto the counter. He spread her legs wide, lined up again, and drove back into her asshole. Now he could watch her face while he fucked her. Her mouth hung open, eyes half-lidded with lust.
He leaned in and sucked one nipple hard, biting just enough to make her yelp and clench around him.
"Play with your pussy while I fuck your ass," he ordered. Emma's fingers flew to her clit, rubbing fast circles. Her other hand reached down to feel where his cock stretched her asshole. "That's it, little sister. Touch it while your big brother uses your tight hole."
She came first, body shaking, asshole pulsing around his cock. Jake kept thrusting through it, chasing his own release. When he was close he pulled out, shoved her to her knees, and stroked his cock over her open mouth. Thick ropes of cum landed on her tongue and lips. She swallowed what she could, then licked the rest off his shaft, sucking the head clean.
They stayed like that for a minute, breathing hard. Jake helped her up and pulled her against him, his cum still on her chin. "Shower with me," he said. "I'm not done with that asshole yet."
Emma smiled, already turning the water back on. "Good. Because I want you to fill it next time."
