Bobby woke up suddenly, with only a little light from the streetlight outside illuminating his room. He checked his watch and saw it was 2:30 AM. He tried to roll over and go back to sleep, but as he did, he gasped.
His nipples had rubbed against the sheets, and it felt really strange. He pulled off the covers and looked at them. They seemed to be getting larger, and more sensitive. He rubbed one of them again, and it swelled more. It felt good- really good. Like he'd grown a dick on his chest. He started rubbing the other, and panted, his body responding to the new feelings excitedly.
He pulled out his cock and started stroking it instinctively, while the other hand pinched and pulled and rubbed at his nipples, quietly revelling in the pleasure he'd discovered. He felt as if his desires were changing; the idea of being fucked, having something inside him filling him up, was becoming very exciting to him.
Almost unnoticed to him, his penis was receding into his body, and his testicles began to move upwards. He was distracted by the progression of his nipples into supple breasts, fondling and admiring himself, until one finger traced across his loose scrotum, rubbing along it as it formed the lips and slit of her new vagina. Her penis was fusing with the rest of her crotch, settling in above her new vagina and tucked into its new hood, forming her tiny but intensely sensitive clitoris.
Bobby was distracted from the dramatic changes to her body by how pleasurable they felt; the newfound pleasure from her nipples, combined with the warm filling feeling of having her own fingers inside her, was pushing her to heights she'd never felt before, and could never feel as a man. She bit her lip hard as she came, her womanhood clenched firmly around her fingers.
Pulling the covers over herself again, she drifted off to sleep.