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When wearing dark pants and dust gets on the butt of them and wont come off.
Man I fell on the floor and now I've got butt dust.
by Often butt duster September 04, 2009
The speckles left on the toilet seat,seen when you get up from taking a dump.

Hay you left butt dust on the toilet seat,get back in the
there and wipe it off.
by OOOO February 24, 2008
noun; the crusty, dusty particles of leftover fecal matter that is left on or around the anus. Occurs when wiping was not adequate.
Dude, yesterday I shook some of my butt dust out in Britney's chocolate milk. She didn't notice a thing, other than a slight nutty taste!
by Mookiechaser July 30, 2009
Dust that comes within the anal cavity unexpectedly.
Jeff farted and his butt got a little smokey afterwards. I said, "Damn dude, did you see that cloud of butt dust you just left on that little kid?"
by Jason January 15, 2004