Karyn then slapped herself for her stupid wish. "Crap, that means whenever a man gets aroused, he will get a vagina instead of a penis, which means girls can't get pregnant from them, and the wish can't be reversed."
She tried thinking of ways to prevent the effect of her stupid wish without reversing it. Then she realized she was wrong. Whenever a man gets aroused? She said "boy".
"I wish that when a boy would get an erection, his sex organs would become a vagina instead, but that once a boy reaches puberty and starts to become a man, he'll slowly gain control, so it won't happen if he doesn't want it to, at least most of the time."