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).