1. The female equivalent of swamp ass
2. The layer of sweat, slime, etc. that accumulates in a woman's ass crack on a hot summer's day.
3. A sweaty condition existing in a woman's ass region. Amplified during exertion and in particularly hot and humid weather.
I normally like to eat out an ass, but after she got back from the gym she had some nasty trunk funk going on so I went with the stinky pinky instead.