"Sis, jack my prick some more!" her kid brother cried anxiously. "Unngggh! Need you to make me cum, Sis!"

Karen tightened her fingers around the base of his cock, marveling at how fat and meaty it felt. Urgently she started jacking her right hand up and down the throbbing fuck organ, beating his meat from the root up to her sucking lips.

Soon her right fist was pumping in a blur, and she was sucking and slurping on the knob so hard that the tiny apartment seemed filled by the sounds of her cock sucking. Cum, Jimmy, cum, she thought feverishly, as she worked nonstop on his meat. Shoot your cum in my mouth, Jimmy! Sis wants a nice, big bellyful of cream!

"I'm making it!" Jimmy groaned, as if he could read her mind. "Urmgggh! Suck my cock, Sis, suck my fucking cock! Cumming now!"

He clutched her head with both hands, grimacing and arching his hips of the couch. Then an enormous stream of pent-up cum spewed out of his cock head, lashing around the interior of Karen's mouth, basting her tonsils with the outflow of his hot, sticky cum.

Karen gurgled as she clung hungrily to big, squirting pisser. She kept sucking and jacking his cock as hard as possible, now working her throat muscles to gulp down the load at the same time. For at least a half-minute straight, her kid brother's boner kept spraying cum down her throat, Karen sucked out every drop of it, refusing to let her kid brother's boner slide out, of her mouth until she'd licked the last traces of cream from the head of his cock.

Then the cock sucking was over. Jimmy sprawled back on the couch, his spit-glistening boner remaining as hard as ever as it twitched and pulsed over his stomach. Karen sat back on her heels and blushed with shame as she licked the stray drops of prick juice from the corners of her mouth.