I picked one of these up in Nakhon Phanom, its a mini fast home brew pot. You fill it with sweet liquid, traditionally coconut or palm juice, and leave it in the warm to ferment for 15 minutes or longer. Dried yeast inside ferments the juice into a semi-alcoholic drink.
Although juice or sugar sap is traditional, one of the best flavors to use is Sprite! It's sweet enough to give the yeast something to work with, and the herbs in the pot work well with the lemon/lime flavors.
I used young coconut juice for mine, young (green) coconut is a little sweeter.