Fuck her ass (and cum in it, too)

"Stop, Beth." You hiss, yanking on her blond hair. Your sister looks up at you inquisitively, frowning slightly. "Take your shorts off and turn around."

Smiling, she did so, wiggling her ass at you as she did so. "Is big brother going to take his little sister's virginity?" She says sweetly.

"That sounds tempting, but I have another idea in mind." You grin, shoving her forward so that she was leaning up against the couch. Smirking, you line your throbbing erection up with her ass. "Get ready, Beth."

Slowly you ease yourself in, making her moan in pain and pleasure as her fingers tightened around the top of the couch. After the first few inches, you ram the rest in in one quick thrust, making her gasp in surprise. Immediately after, your hands clutching her waist, you begin thrusting in and out of her vice-like anus, as her grunts of pain turned into moans of pleasure.

"Oh, god...John...do it harder..." She moans, turning her head to stare lustily at you. "Fuck your baby sisters ass, come on..."

Those words almost drove you over the edge. You sped up, pulling almost all the way out and then ramming back in, practically forcing her forwards with every thrust, and her screams of pleasure grew even louder. Soon, you felt your orgasm swelling up, and with a few more thrusts you cum explosively inside your little sister's ass. Slowly, you pull out, letting her slump against the sofa, exhausted, your load trickling out of her small hole down her legs.

"Thanks...bro..." She gasps. "What's next?"