Giant Horse Vagina

A moustache is sometimes called a Giant Horse Vagina, due to it's utterly close resemblance to an actual horse's vagina. Moustaches also go by a few other names, such as Soup Strainer, Lip Whiskers. First used by Peter Griffin from Family Guy.

Meg: OMG Peter, What's on your face???
Peter: Meg, it goes by many names, soup strainer, lip whiskers, and until very recently, giant horse vagina, but I prefer the term moustache.
Wife: ooh, I think it's sexy!