You were so sleepy, that you couldn't wake up, until it was the next morning. because you were in the middle of some dream where you pretended that you were riding a horse. All of a sudden, you heard that the horse sounded like that centaur mare you talked with, Frankie, as you felt that you were becoming a horse yourself.
The rooster woke you up from the weird dream, as your eyes start to open, at the same time. All of a sudden, you feel funny from the odd dream. You check all over your body, and finally check your privates, finding that your penis was longer, as you were now erect with a changed shaft at the top. Not only that, but your balls were becoming a darker shade, while the rest of your penis was becoming pinker than it usually is. You weren't sure how, or why it changed, but you needed to keep it from your uncle.
So to get rid of the massive erection you now had, you got off the mattress, and left the bedroom, to go find a bathroom, and fill it with enough cum to restore your penis to normal.