dirty Sanchez noun1 •(slang, vulgar) After anal sex, the act of drawing a mustache on the recipient's face with the object of penetration (usually a penis).I told her, repeatedly, that the only thing I wanted to do on my birthday was give her a dirty Sanchez, which I think is doubly appropriate for my little wetback slut. — 2002 formsdirty Sanchezes · dirty sanchezes