When a man and a woman are
having sex in a bed and the man lays on his back, his penis erect, and the woman jumps into the air off the mattress and tries to aim her self in such a way that her vagina lands over the man's penis (his penis entering her vagina) leaving him unharmed. It is like the game of
horse shoes because you have to try to land an object (the vagina) around a pole (
the penis).