She thought about how thing would be different without her hormones. She didn't know if an adult could masturbate if they didn't go through puberty. She'd definitely miss self pleasure once she closed the book.
She decided to get one last masturbation session in before she transformed. She pulled out her phone and started looking at some porn while stuffing the other hand down her pants. There was something super hot about masturbating while not knowing if you ever will again. She looked at pictures of girl's boobs knowing that pretty soon there wouldn't be breasts. Watched boys jerk off and cum knowing that soon there would be no fertile seed. Enjoying the last of a world she would soon destroy.
Then she finally orgasmed. She moaned loudly knowing it would be her last. After that she was exited to finally transform.
She slammed the book shut and watched the world change. First the girl on her phone went from showing off her tits to showing off tiny pale nipples. Then claire noticed herself change. Her breasts shrunk down until all that was left was the same flat chest she had as a child. Then her figure slimmed out until she had no feminine hips and a flat butt. Her skin became smoother and her body hair faded. Finally she noticed her crotch dried up as if she never masturbated, any physical arousal ceased and her vagina shrunk down until it was the same size and shape she had when she was a kid. She'd done it, she'd become a pre pubescent adult.