Very high quality pussy. A beautiful, sexy woman who's had very few sexual partners but is without a doubt amazing in bed. Quite likely has a snapback vagina that is very well maintained and clean. Koontash is very difficult to get in bed but is always worth the effort. The opposite of koontash is poontang.
"That foxy lady over there, now that's what I call koontash!"
"I'm tired of poontang, I need me some quality koontash."