It is a very unique, undescribable flavor..... a little bit thicker than milk (in my opinion), and you can taste and smell the spices and other things in it.
I love eggnog. I would describe as something like this... Thick and creamy, fills you up fast so don't pour a big glass of it. Tastes slightly like milk and eggs. You should at least give it a chance.
EGGNOG!!! I love it. They way it is made sounds nasty but they put cinnamon in it and it taste delicious. Well, almost all "cinnamon" in the US is not really cinnamomum verum, but cinnamomum aromaticum, which is Cassia. A member of the same family, but not quite as delicious.
Anyway, try the non alcoholic one. It is delicious. I could drink it all day. So sweet.