A sexual act. While the man is standing with feet a little more than shoulder width apart, he then bends at the knees lowering his crotch straight down (a squat) to make penetration to the female below. The Oompa Loompas would bend/bounce like this when they sang the "Oompa Loompa" song, which is how the act got its name
by Rand McNally November 27, 2006