Harry Houdini
A sexual act where a guy is having sex with a girl doggie-style and is about ready to blow his load. He spits on the girl's back so that she'll think he's done. She turns around, never suspecting that the guy has his loaded piece ready to go. The guy then spunks right in the girl's eyes and he disappears quicker than Harry Houdini.
Man, I was screwing this chick last night, but I didn't want to get tied up in post-sex conversation. I utilized the infamous "Harry Houdidi" and got the heck out of there.