Pour in the eggnog and milk

• Pour the eggnog into a gallon-size container.
• Add the milk to thin out the eggnog; skip it if you prefer a very thick drink.

Spike with the rum

• Pour in the spiced rum, doubling it if you want a stronger drink.
• Stir and taste, adding a little more rum if needed.

Season and stir

• Add the cinnamon and nutmeg, using slightly less nutmeg than cinnamon.
• Stir in the vanilla extract.
• Mix well and taste, adjusting if desired.

Chill and serve

• Let the drink rest overnight so the spices fully combine.
• Serve over ice, sprinkled with cinnamon and garnished with a cinnamon stick.