When one sticks one's finger up a girls azz and then wipes it under her nose, leaving a "mustache".
Man, you should've seen the look on her face when I gave her a Nasty Sanchez.
the act of sticking a finger in one's own ass and rubbing it against their partner's upper lip, not to be confused with the dirty sanchez
which differs because one inserts one's finger into their partner's ass before such lip smearing.
dude, i was railing my neighbors sister the other night, my hemmoroids were acting up so I scratched my booty and came up with a plum, couldn't waste it so i gave that bitch a nasty sanchez
see: Dirty Sanchez
confusion over the word Dirty and Nasty brought the creation of "Dirty Sanchez" when in reality, the Slang term derives from "NASTY Sanchez"
Fred Norris went to a gay bar, ended up drunk in a gay wrestlers pad, laid flat on his back with his ankles pinned to the back of his ears. The gay wrestler pulled out and wiped his shit filled penis on Freds upper lip giving him a Nasty Sanchez.
Fucking a girl in the ass then making her suck your dick.
"I gave Lola a nasty sanchez. I wonder if she brushed her teeth."