The act of taking a dump in a public restroom and leaving the stall door open slightly. You do this in attempt to catch an unsuspecting person by surprise and see the shock on their face when they walk in on you blowing mudd. Don't confuse this with open faced dump.
Oh it was the greatest, I knew Trevor's brother would come in soon so I snuck in there and took a dump at face value. You should have seen his face! I don't know if it just seeing me there or the fumes, but he had tears in his eyes!