Culture comes into play when you are even involved a simple task like downing a few pegs with the company of friends. Look into the eyes and also don't cross the glass while raising yours for a toast. Those are the few that I know. But there is always an opportunity to learn new ones.
Normally you don't place your glass back on the table after raising it for a toast. You take a sip and enjoy it spreading into your body before gently placing your glass back. Apparently, it is not so in some cultures. After the toast, you place it on the table first after which you pick it up to actually drink!
That was an interesting lesson. But there was one more learning from the evening. What do you do first when you pick up a bottle of wine to fill your glass? If you are like me, then you look around and ask the others if they need a refill. But in some cultures, it is rude to pour drink for another person!