Which glass is commonly used for serving a B-52 cocktail?

The B-52 cocktail is traditionally served in a shot glass. This is because the B-52 is designed to be a layered shot, showcasing the distinct layers of its ingredients: coffee liqueur, Irish cream, and orange liqueur. The shot glass allows for the visual appeal of the layers to be appreciated, as well as facilitating the intended consumption method, which is to drink it in one gulp.

Using a shot glass enhances the experience of the B-52, allowing bartenders to create the layers effectively, and it's the glass most commonly associated with this type of drink. Other glasses, such as a highball glass or pint glass, would not only diminish the visual presentation but are also generally used for other types of cocktails or beverages that require different serving sizes. A martini glass, while elegant, is also inappropriate for a B-52, as it does not serve the layered characteristics of this particular cocktail.