When the mens room at your office building has not been cleaned for an amount of time that allows the rim of the urinal to collect pubic hair. The collection then appears like a mustache on the rim.
I almost puked when I had to use the restroom and the urinal mustache tickled my hand.
The greatest person ever. Makes everybody drool (guys and girls alike), but is determined to stay an eternal virgin. He is vulnerable to STDs due to his micro-penis
Friend: "Yooo look at that absolute sex magnet!"
Other Friend: "That's the holy Mustayeen bro"