Reverse Kangaroo (Reverse Kanga)
The Reverse Kangaroo or "Reverse Kanga" is the act (or art) of sitting backward on a toilet, thereby leaving a long, filthy skid mark down the length of the bowl. Popular in public toilets and the mother-in-law's house.
That bitch gave me shit about leaving the toilet seat up, so I pulled a reverse kanga and left six inches of skid for her to clean up.