Background:

Thursday nights are my usual Meetup group's game night, and the one I don't get to go to much during the school year. (We also play on Saturday afternoons.) Last night, a couple of parties had booked our usual space in the bar, so we were on a few really small tables near the four pool tables in the side room.

I'm about 2/3 of the way through the game I'm playing with a couple other folks when one of the women near the pool tables catches my eye. I was not doing well at the game in the first place (came in 2nd much to my eventual surprise), and started spending a lot of the downtime between my turns checking her out. And I'm pretty sure she knows I was checking her out, because I think I caught her looking at me a couple of times, too. Just as I've decided that I'm going to have the barkeeper send her a drink when I go to settle my tab from dinner, I realize that she's there with another guy.

So: I continued to eye her from across the room up until I left, but never made any kind of a move. But if you're poly/in an open relationship/swinger and had been at least a little bit interested in the guy who's spent a decent chunk of the last 90 minutes eyeing you and your ass in the white slacks you're wearing as you bend over to play pool (sadly, she wasn't bending toward me often), how might you communicate that interest when you're also clearly there with another guy?