Downstairs Mustache 

pubic hair

Her downstairs mustache was so dirty it had a whole ecosystem living in it.

Downstairs Mustache by gimmiesumgrain August 29, 2010

Downstairs Mustache 

The collection of hair in the pubic region shaped in the form of a mustache.

"The other day I was at my cousin's birthday party and I flashed my downstairs mustache, because it was Mustache March."
"Dude, your cousin is like seven."
"You must(ache) be mistaking me for someone who gives a shit."

Downstairs Mustache by Richard Flavor May 18, 2014