A wonderful addition to the set of common vernacular describing a womans genitalia. It is usually used to reference the "snatch" of a filthy or dirty whore. As for the reason that the "snatch" might be called soupy, I leave as an exercise for the reader.
"Yeah, I was starting to go down on Tina but her soupy snatch invoked my gag reflex."
by MiddleAgedMike November 17, 2007