Your basic game of No Limit Texas Hold 'Em except you bet with drinks. Obviously, the winner of the round doesn't have to take the drinks. The loser(s) has to drink the number of drinks that has been bet.
Example: I bet 10 drinks. Another player sees my 10 and raises another 5. I call. This makes the number of drinks the loser has to take 15.
If you fold, you have to take the drinks that you bet.
A few tips: Limits on bets are suggested but playing w/out them can enhance the drinking experience.