We had sex.
Okay, yeah, we're teenagers, and underage, and not supposed to, but honestly, my parents were gone for the weekend and Lily's mom had teleported off to Timbuktu for a witches convention, so what do you think was going to happen?
Of course, she was a virgin. So was I. And we were kind of fumbling with the whole thing and I was incredibly hard and she was incredibly tight and then she said, "Stop, you're hurting me..."
And then we both paused as we realized what she'd said.
And then I started to get harder and harder and I suddenly realized that my dick was turning into a donkey dick.
Lily smiled. "Don't worry, this was part of my plan."
"What?" I brayed and then realized that my ears were getting longer as well. "You wanted me to turn into a donkey?"
Lily giggled. "My mom thinks she's so clever. She thought the old donkey curse would be a problem, but she'll reverse it as soon as she gets back."
"Why?" I brayed, getting even more scared but even harder.
Lily grinned. "Because," she said, "if she doesn't, she's going to have pictures of her daughter having sex with a donkey all over the world wide web." Lily paused. "Actually, I've got an even better idea. I'm not up to full transformations and transfigurations yet, but I can still pull off a simple glamour."
She brushed her fingers over her face and her features changed slightly and aged and the next thing I knew, she looked just like her mom. "Mrs. Gershwin?" I brayed.
"No," she giggled with Lily's voice, "I'm still Lily. But the web camera won't know that." She waved a hand and her computer popped on, the camera whirring to life, then she looked at me and purred, "Make me a desperate housewife, donkey boy!"
Donkeys are incredibly horny, and Mrs. Gershwin's vagina was considerably looser than Lily's, for all that it was just a minor transformation.
I kept turning into a donkey as we made the beast with two backs along with kinky blackmail video for Lily's mom.