This is interesting.
In this situation, I would interpret it as the person wants to "take a lap" of the bar/party. Which would mean moving around and talking to people. Also known as "working the room." In this situation, it would be acceptable for the person to take their drink with them which would explain the bottle of wine in hand.
If they were talking about a round of drinks, it would have been more common for them to say "Who's round is it?" "Do we need another round?" "Let's get a round" etc....
Hope this helps