Someone who has very dry, pasty lips.
"Damn nigga, you done got some crusty ass lips! You crusty ass, dry mothafuckin bitch!"
Crusty is an adjective describing how someone is. Crusty: gross, smelly, rarely showers.
David: Hey bro, do you smell that?
John: Yeah.
(Both boys look to the side.)
David: UGH! She is crusty.
Describes something/someone disgusting
I know Jaelynn wants the D, but she's a crusty ass bitch so I ain't givin' it to her.
A thirsty boy who has participated in a loving wank with his right hand resulting in a sticky mess which is then not washed off for at least 2 days
That girl made him crusty, he be crusting over her all night long