Drinking an alcoholic beverage, usually beer, at the same time with two or more people at the beginning of a social party/drinking game. Commonly used at the start of flippy cup, drinking a shot with others, etc.
When drinking a combination shot, such as an Irish Car Bomb, or vegas bomb, where there is a small shot glass full of booze, and a pint glass half full of beer or red bull; the entire shot is consumed by dropping the small shot glass into the half full pint glass, typically preceded by a cheers. Thus Clink: raise and tap shot glasses, Sink: Drop shot glasses into pint glass, and Drink: Consume the entire beverage.