A Buffalo Nickel is a piece of dookie stuck to the back of a toilet. Usually caused by explosive diarrhea. Derived from the small pieces of feces that stick to to the hair on a buffalos ass. Not to be confused with skid marks from a flush. The Nickel part of the word is used to describe the usual size of the spayed fecal matter.
Aww man I flushed 3 times and the Buffalo Nickels are still there.
Dude I can't find a clean shitter they have Buffalo Nickles all over them.