Close cousin to the highly acclaimed and practiced
Dirty Sanchez, this maneuver, usually made during doggy style sex, involves putting your finger in your own ass before wiping it across your partner's upper lip, creating an
authentic looking
mexican moustache. Presumably you would use this technique when your partner's ass is too well cleaned, or it's already full of your cock. Bonus points for getting a whole fast food order out before your partner gets their lip cleaned off.