Verb - The act of dropping a steaming dump into the water tank of a toilet. It's very important to replace the tank cover and leave the room as if nothing happened. Each future flush will reinvigorate the stench of slowly eroding water tank dump.
Frat Guy 1, "Did you end up fighting those guys at that party last night?"
Frat Guy 2, "Naw, I top shelfed those bastards... they'll be smelling that fudge for weeks!"