That very annoying occurrence in which water shoots directly up ones ass as they are going number 2. It only occurs when the "units" hitting the water are of a certain size, shape and weight and the water line is at a certain height. The most annoying thing is once it has happened to you enough times you know its about to happen when you are going and there is not a god damn thing you can do about it. According to my girl friend this has NEVER happened to her. Some of us should be so lucky.