When a man inserts his penis (or in this case, "Gnome") into a woman's anal orifice. Said woman must be ready for the "Gnome" to plow her cornhole. Once penis is inserted, grab woman's face and slam the back of her head onto the hard part of the bed. Booyah!
Suzy, what the fuck happened to your head?
Well, Jennifer, Curtis gave me an anal gnome last night. That gnome was a real bastard.