When a chick is nice and wet, throw a couple digits inside her vag. Take those wet fingers out, and give the 2 finger sniff across your mustache line. Leaving a glistening trail of vag juice across your upper lip and below the nostrils for one to smell and enjoy. Hence, the Clean Sanchez!
Alternatively, it can be done on either yourself or on the chick you just fingered
Guy 1: After some heavy over the clothes touching and making out, she was right into it and super wet so I gave myself a Clean Sanchez
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"