It's the holidays--I have so many questions for you. First of all, what time of day is appropriate to start drinking eggnog?
Because eggnog has eggs in it, and eggs are a standard breakfast food, it's fine to drink this beverage upon waking. Most enjoy it at cocktail hour or after dinner, though, as a dessert drink. As a general rule, the holidays are a time when normal expectations are relaxed, so feel free to enjoy eggnog any time of day.