Shake before each use.
Do not blend in a blender or you can cause thickening to occur.
Do not use pudding based eggnog. These are often called mock eggnog and are most often homemade. This will make the creamer extra thick and cause your coffee to gain a film at the top of it.
Unless you want to be buzzin’ in the morning, avoid eggnog that’s been spiked. I use basic store-bought eggnog.
If you need to use something other than half and half, opt for whole milk, evaporated milk, or even coconut milk.