When drinking with Bulgarians, it is important to observe the ritual of cheers. The Bulgarian word for “Cheers” is “Nazdráve” (literally, “on health”). You may state it loudly once in the overall din, but it is important to make eye contact with every drinking companion as your glasses or bottles touch. Subsequent rounds of salutation may occur, in which case the same rules apply.
It also helps to understand the social role of drinking in Bulgaria. In most cases the consumption of alcohol is aimed less at getting drunk and more at facilitating social interactions. Alcohol is consumed in grand quantities, but at a leisurely pace, never downed at once, and it is almost unfailingly coupled with some sort of accompanying snack. The Russians call this “zakuski”, while in Bulgaria we prefer the Turkish word “meze”. Meze is typically served alongside rakia, vodka or wine. As expected, each type of alcohol calls for different types of meze.
Vodka is best consumed neat, alongside a glass of tomato juice or with pickles, pickled fish or kiselo zele. Blended whiskey is paired with salted nuts (peanuts, almonds, cashews, hazelnuts), while single malt whiskey can and should be consumed without meze.
(Thanks to Blazing Bulgaria for this very useful info!)