When a woman has neglected her self-respect and personal hygiene to the point of masturbating after eating a bag of Cheetos, or any other cheese snack for that matter, without cleaning off her fingers. The result is a Cheeto Dust Taco.
The vagina of a lonely woman, who hasn't had sex or masturbated in a couple weeks at least. She is a very sad sight to see. The term "dusty taco" refers to the human embodiment of depression and loneliness. The women with a dusty taco are usually under age or about ready to commit suicide. Either way, it is very to approach a girl with a dusty taco.