1 definition by Milky~Chan
The sexual act of skull-fucking a horse then shoving your penis through its skull making it look like it has a horn.
boy 1: Hey did you see that? Is it a unicorn???
boy 2: Nah man my friend told me he was going to unicorn a horse.
boy 2: Nah man my friend told me he was going to unicorn a horse.
by Milky~Chan March 16, 2010