when a girl sticks her hand down her pants in to a rank 4 day old vagina (right before creeping up behind you) and smearing it in the form of a mustache on your face thus rendering you either unconscious, gay or under her control for an indefinite amount of time..
The dirty martita derives its name from the dirty sanchez but is considered much more tasteful. The dirty martita is currently being used as the preferred secret weapon of many woman's revolutionary movements taking place WORLDWIDE.
Your only defense against the dirty martita is forcefully countering with plumpkin but you must be careful considering the plumpkin has some technical variables you will have to worry about to ensure your safety.
If the dirty martita should be administered on you and you can not seem to break the smell, er... spell... rumor has it you will first go through hell for many years while remaining safe and eventually being restored to your original senses only to spend the rest of your life chasing the scent.
Tug job Terry, played by Nick Swardson on Reno 911, was supposedly under the effects of a dirty martita applied back in grade school.
No examples except tug job terry. nearly impossible to see the dirty martita coming and it has yet to be captured on video.