When a friend, partner or acquaintance plugs your anus with their fist when you have an extreme case of diarrhea, thus stopping the leak. If done incorrectly, the excrement will run down the partner's arm.
Ex 1: Bob: Aww man, I've got anal leakage again. Time to call the plumber
Joe: ... What the fuck is wrong with you?
Ex 2: Maria! Your crappy Mexican food gave me an assquake!