You need a Keg of Chugging. Like a Decanter of Endless Water, but it's ~~beer~~ a potion. If a character begins drinking from the Keg of Chugging, he must make a CON save every round. He may not stop drinking until he fails the save, and he may not voluntary fail the save. Once he fails the save, he stops drinking but becomes fatigued. On every round after the first, any creature which is capable of speech and can see the character must make a WIS save or be forced to pass its turn while chanting "Chug! Chug! Chug!"