A dusty bumper is the action of falling ass-first into the dirt while ones pants are around their ankles. Common during rowdy outdoor sex and defecating in the woods. If the latter is the cause of the dusty bumper, one may walk away with a rusty bumper.
Earl: Last night, I was beatin' cheeks with Becky in them woods right behind my trailer, when i tripped over a stob and gave myself a dusty bumper!
Jim-Bob: Well hell yeah brother, than poon is totally worth it! Fuckin' ain't nuthin' if she ain't yer cousin! Yeeeehaw!!
One of Buffalo Bill's first victims in Silence of the Lambs. She is described as "a great big fat person." The term is now generally used to be describe someone who is both overweight and unlucky. Repeated mentions by Jimmy Norton of The Opie and Anthony Show drive the popularity of the term.
"It seems old Frederica Bimmel over there is having some difficulty loading her couch into the van. We should help before she breaks an arm."