When you blow your load on a girls face, then either using your own or preferably her pubs to put on her upper lip. When no pubic hair is available use ass hair. It then resembles a mexican moustache, no offence to mexicans. ;)
Dude: "Oh yeah, I'm gonna come"
- commences facial
Broad: "Oh yeah I love it"
Dude: rips her ass hair out and puts on her lip
Broad: "Owww!!! What the fuck?!?!"
Dude: "Mexican Moustache Bitch!!!"
A thin, sorry excuse for facial hair consisting of a few scraggly, individually visible hairs scattered above a man's upper lip. Typically seen on teenage boys who can't yet grow a full moustache, and on men from ethnic backgrounds that typically have sparse facial hair. Pathetic for the same reasons as a comb-over, and very low class.
Jimbob's luck changed one day when he shaved off his mullet and his Mexican moustache. Someplace called him back for a job interview that wasn't a gas station.