Poo Chop
The act of taking one's hand and swinging upward into the colon of an unsuspecting victim, thus causing them to poo their pants.
A friend of my once did this to my buddy. The victim was picking something off the ground when the suspect "Poo Chopped" him right in the sphincter causing him to drop a deuce in his whitey-tighties, and run for the nearest "john".