The crusty brown material that gets transferred to the rear of the toilet seat or underwear, resulting from the accumulation of fecal matter at the top of an unclean, too-far-rear-wiping person's ass crack.
by Etch August 15, 2006
after 'releasing' waste products, the part that 'hangs on'. also an insult to persons of idiotic disposition.
'you dropped that expensive glass! - you butt smudge!' or 'ewww...my undies are stuck to my butt...it must be that little be of butt smudge left'
by mel p November 30, 2004