Dirty Sanchez - During doggystyle sex, the male inserts his finger into his partner's anus. He then proceeds to smear the fecal matter onto his partner's upper lip to create a mustache made of poo.
2) After doggystyle sex, turn her around and stick your dick in her mouth. The fecal matter that was on the tip of your dick will now form a nice brown mustache above her lips. - Adam K
3) When a man is having anal sex with a woman doggystyle, then he pulls out his feces covered pecker and rubs it on the woman's top lip, giving her a "Dirty Sanchez". - Justin