Fill a large jug full of beer. In the beer, insert a shot glass so that it is floating in the beer.
The players take it in turns to pour any amount of any spirit they choose into the shot glass. The person who pours the spirit that causes the shot glass to sink in the beer must drink a penalty. They must dip their own glass into the jug (or pour some into their glass) and drink a pre-agreed amount. We suggest that 4 fingers is suitable.
The shot glass is retrieved and play starts again with the next player taking their turn to pour some spirit into the shot glass. Each time the shot glass sinks the infringing player must drink four fingers from the jug. With each passing turn the concentration of spirits in the beer becomes more potent.