What does Apple juice roulette mean?

Apple juice roulette meaning in Urban Dictionary

An obscure celebration game played by pranksters, frat men, and friends alike. The video game is enjoyed multiple glasses of apple juice, how many is around the gamer. One cup is full of piss. The players each story a glass and take in until some body drinks the piss. Some people prefer to change this into a prank and fill all of the specs with piss.