1. A term for a woman's vagina, when receiving cunnilingus, has a sharp, sour, foul taste reminiscent to that of the condiment mustard.
2. A term for a woman's vagina that gives off such a foul odor so strong that it could result in casualties, much like Mustard Gas.
"Damn, girl. You need to do something about that mustard biscuit you got between your legs."