I HATE THIS FUCKING FORUM

A dirty Sanchez or filthy Sanchez is a term describing the result of a person having a "mustache" made primarily of fecal matter or other "ass residue" or dookie. It is also called a Dirty Mexican in the Midwestern U.S., a Dirty Contreras in Oregon and a Dirty Mungy in Florida and California. Although a Filthy Sanchez is also defined as recieving oral sex while defecating on a toilet.

This may involve the action of inserting one's finger or penis in the partner's anus and smearing the dipped finger or penis across the partner's upper lip, effectively creating what may be viewed as a "mustache." One school of urban legend thought, albeit jingoistic, holds that the result is supposed to make the partner appear "more Mexican," which is where the name purpotedly originates. A variant is the Dirty Sanchez à la mode, where, immediately following ejaculation during anal sex, the penis is used to smear a creamy fecal matter/semen mixture above the upper lip. While not considered a Dirty Sanchez proper, another example may involve engaging in an ass to mouth action whereby a penis is placed in a person's anus and removed, where upon fellatio is performed. As the fellatio is being performed, fecal matter on the penis may collect on the lip of the person performing the fellatio, thereby resulting in the "fecal mustache," or more likely a donut hole.

Whether the practice is common or not, it has become common currency in the realm of urban legends. There is at least an amateur looking porn movie circulating on the internet in which the girl's chin is touched by a penis dirty with her own feces, during the facial.

 

In England, that's called a 'Blooper'.

Most commonly performed during a bout of doggy-style vaginal sex.