The performer takes a finger and inserts it into their buttcrack until a healthy
brown smudge is harvested. An unsuspecting victim is then carefully and quietly approached, and at the right moment the dirty digit is rubbed/smeared on the victim, in the thin
space above their upper
lip and below their nostrils.
The result, a
brown and smelly temporary moustache, is known as the "stinky sanchez." Alternative titles include the "dirty hitler," "brown rollie" and "tom selleck."
For extra points, perform it on a sleeping victim.
My
roommate Tom fell asleep on the
couch, and i gave him a dirty sanchez. He woke up and walked around the
house with it for a while before he looked in the mirror and started shouting.