It's the art of the double dip on a divorced lady who hasn't had sex in years. You do her in the butt, and she has bloody stool. Then, while having tons of bloody shit on your dick, you slide it into her bloody period vag, thus resulting in a brown/red vagina-or a Rusty Taco.
Picking up the last skanky cougar at a bar, usually with wrinkly overly bronzed tits, sporting a Sturgis t-shirt and you wonder how the fuck she burns down so many Marb Reds without igniting her 80's glamour shot hair sprayed pube farm of hair. Also, guaranteed to give you a bj in a dumpster while wearing ass-less chaps that are coated in her rusty taco sauce. She may be missing a tooth, but she can suck a mean hog as she most likely started blowing Hells Angel thugs at age 17.
an older womans vagina(80 years or older) usually dripping an odd smelling substance.
jay and deans mom has a rusty taco