After having anal sex with an old woman, she shits on your dick and then sucks it off. (Not to be confused with the Moist Keith when its a young woman.)
Eric: Dude, your mom's breath smells like shit!
Thomas: Yeah I know, she just gave my dad a Crusty Keith.
Thomas: Yeah I know, she just gave my dad a Crusty Keith.
by hobojoe017 June 8, 2011