It is a noun and an adjective. When someone does something characteristic of a white trash person, you can say. That is so White-T. As a noun, You are totally White T.
A fake mocha drink made generally made from leftover coffee and either hot chocolate mix or powder mocha mix. The resulting drink tastes nothing like a legitimate mocha.
Mark: What the hell are you drinking?
Jason: There wasn't enough coffee in the pot for a whole cup so I added some hot chocolate powder to make a white trash mocha.
When you get cum in your asshole and fart it out like white mist.
Billy had so much cum in his asshole that when he attempted to white mist his daddy all that came out was a brownish whitish sludge that drizzled down his gooch.