A Dirty Teen Mustache is a mustache that some teenagers thinks looks cool on them, but it doesn't. It's like the kid isn't meant to have a mustache, but he has one anyway. That's called a dirty teen mustache.
bawb: Hey, what's up with the mustache?
John: Oh, right, how's it look :D.
bawb: uh, no. Shave that Dirty Teen Mustache off.
Always on a Female, it's when she first notices small bit of fluff on her upper lip, she then shaves it off- not knowing that for life she is going to have a dirty moustache. She will then try to cover it up with some cheap poundshop makeup.
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.