There are only two rules - one, a drink is a simple sip of the alcholoic beverage in question. Do not drain the container unless specifically mentioned to. You want beer, you watch movie. A samurai who isn't part of the main cast wanders on screen. You hear drums in the background.
Someone tries to run really fast.
The peasants act like total idiots and run to the Grandpa for help, despite the fact that they're all grown-ups and are probably capable of thinking for themselves. Whenever a bandit falls off his horse. Every time someone dies. Whenever a peasant breaks into bitter tears. Has to remind himself he's bald by rubbing his head.