After fucking a girl in her ass. you remove your shit covered dick and write your two initials on either side of her butt cheeks.
"I pulled out of that chicks ass, and gave her a dirty zorro. Afterward I bent her over and she spelled B.O.P."
by Charger Brent September 30, 2006
Like a "Dirty Sanchez", but involving anal sex... You whip out your cock and run around to her face and in a flourish indicative of the masked man himself, cross hr face with a "dirty Z" across her face....
by Nordlaw November 27, 2013