Sticky residue, also know as semen, left above the upper lip of the person who just gave a blow job. The semen dries to give the appearance of a white mustache. Got cum?
The fuckin’ cumstache I left on Miss Stewart made the bitch look like Santa Clause in a snow storm, ho ho ho, bitch!
ayon kay Pimp Daddy Chad ika-03 ng Mayo, 2003
A mustache of semen (cum) that is delacately layed on the upper lip of a female, or in a homosexuals case on the upper lip of a man. This can be licked off by any partner and deposited into a sink or swallowed. Make sure there are no STD's while preforming this sexual activity. Best done after oral sex.
Dude i was gettin head from this chick and i cumed on her face and made a cumstache outta it... it was gnarly. it was a true work of art! She swallowed it and everything!
ayon kay Alex Ostrow ika-18 ng Abril, 2006
After the act of oral sex, on occasion the partner's cum is left behind on the upper lip, under the nose. This can resemble a mustache and commonly confused as a milk mustache.
ayon kay Knifo ika-23 ng Agosto, 2011