Wet substance remaining in the anus. Can be caused by lubricants, semen and even crap from a poopdick.
Roy had a yuckbutt after a pleasent evening with Troy.
by Justin W September 28, 2005
A sweaty ass. See "swamp ass".
"Walking around all day gave me yuck butt!" or "Too much walking gives me the yucks!"
by A Doggy Dog December 07, 2008