A female (generally one who is not overly attractive) who lives not only a promiscuous, but trashy existence. Common traits of Dirt Serpents can be high tolerance of alcohol, poor fashion and style sense, inability to dance, crude and vulgar conversational skills and of course lacking sexual scruple's.
Bill: Britney Spears is such a dirt serpent
Ted: Yeah man
Bill: I'd still fuck her though
Ted: Oh yeah for sure!