A finger is inserted into the vagina that is currently menstruating. The finger is then withdrawn and smeared across the upper lip of an unsuspecting victim. It is similar to a dirty Sanchez, except in the place of feces, menstrual fluid (blood, mucus and vaginal fluid and traces of yeast).
Can be both a form of punishment or sexual fetish act.
Ex. 1: "My boyfriend is really pissing me off right now, I'm thinking about giving him a ginger moustache tonight after he falls asleep."
Ex. 2: "FUCKING HELL! you GINGER MOUSTACHED me after I passed out last night! GROSS!"