Ronny starred down at Donna's sleek naked female body, even through he knew she was his brother. The horny teenager just couldn't resist, as Tom left Ronny dropped his jean's. And crawls between her thigh's spreading them wide. Donna's eye's snapped open,she found her hands pinned down as a burr headed teen on top of her grunted and pumped his throbbing penis into her. Glancing down stunned she watched his organ thrust in and out for a few seconds. Then looked up at his wickedly grinning face, red and sweaty with strain as he thrusted.
"Ahamammmm!" She moaned, as the pleasure of it filled her body.
"Liking that huh?" He grunted smiling gloatingly. Donna was to embarrassed to answer...to admit that she was indeed enjoying it. Ronny's thrusts became wild...even frantic as his red sweaty face contorted. And then he was panting and groaning in orgasm, Donna could feel his hot gwooy cum spurting into her. And then the world seemed to shimmer, a pain ran through her loin's. Ronny's closed eye's shot open wide, his jaw slackening in a silent scream. Ronny glanced down at his aching loin's, watching as his manhood became smaller and smaller. Pulling up away from Donna's pussy. They both looking on in shock and disbelief, as Ronny's cock and ball's shrank and shriveled away. It was just an inch long now... They watched it shrink to a small pink bud. "Oh fuck noooo!" Ronny moaned gasping as his voice cracked becoming high and feminine. Donna smiled as she watch the her brother's long and thick manhood tranform into a virgin female sex much like her own! "Oh hell yeah!" Donna purred in glee. As her new sister's pale smooth flesh between her leg's, a new opening; a vagina budded opened before her eyes. Roni stared at her trembling hands, as they softened becaming slender and feminine. Along with the rest of her body, long sleek legs; smooth tight stomach. Her eyes rolled back, as a new miserable agony throbbed within her chest. Groaning as she felt her chest bulge, into firm well shape; if not large breasts. "Fuck!" Roni exclaimed weakly as her eye's roll back and she passed out.