Right after, Kat began feeling a bit dizzy. She barely got herself back onto the bed before she passed out.
Dan felt himself transfer into something; something that was very tired. The feeling of overwhelming exhaustion hit him like a truck and he passed out near instantly.
The next morning, Dan woke up in Kat's bed. Sitting up and stretching, he-...
Wait, what? Looking at his hands, he soon realized that they were not his own, but Kat's! Thinking back to what he could very vaguely remember of last night, he thought he'd read the correct spell. Picking up the book that had been haphazardly left open on the ground, he read through it again, only to realize that the spell needed a body to transfer into to work properly. Kat was not going to like this.
Kat, meanwhile, had been turmed into Dan's (her own?) vagina. She stirred in her sleep, smacking her lips together and wiggling a bit in her new confines. Dan shuttered at the feeling; lying back down on the bed. He began to finger himself to relieve a new tension that had begun building itself in his (her?) nethers. He also groped at Kat's (his?) tits, which grew larger with his arousal.
In his head, he heard Kat moaning quietly, every so often clenching around his fingers. Dan needed this.