A sex act where the the female is on top of the male in cowgirl position. The male then pushes upwards with his pelvis until he is in the classic "The Exorcist" crab walk position. The girl then proceeds to grind upon the mans penis in the air. Often, she will be suspended completely in the air.
I totally performed an exorcism on my girlfriend last night.
You could say, I was The Exorcist. *wink wink, nudge nudge*