Wyoming Weed whacker
During sex in the missionary position, the man grasps the woman (or other) by the ankles and lifts them up. Then he promptly begins to spin rapidly, using centrifugal force to keep the person up-right. This usually ends in the person that is being weed whacked in a mess of their own stomach contents.
"Oh... well uh... I knocked over these lamps while giving Marsha the, er, Wyoming Weed Whacker..."