The politics of accepting a drink

So I'm flailing away on the dance floor, very very happy to be letting off steam after a long week at work [and by the way, on a side note, my boss and I have started to talking to each.other.like.this. gritted teeth and angry tones are always conducive to a productive relationship.]

So anyway, I'm flailing when a very very good looking Irish guy comes up and puts the dance moves on me. He gets in front and starts pulling out the fancy footwork and then it's my cue to follow.

Campbell and Dealergirl start giving me shiny eye, open mouth, thumbs up faces.

What the heck, I'm hardly going to pull a Run DMC vs Jason Nevins in heels. This is not fair. Life is not fair. Oh what the hell, you only live once. [On the other hand, I love each and every one of my shoes as my children so breaking them is not really an option.]

So I gamely follow and you know it was kinda fun? But everytime he came too close, I had to slide [!] backwards and pull the 'ohnoyoudont' hand motions. And then he would give me apology hands. We were a mime's delight.

"So do you want a drink?" I nodded and we went up to the bar.
"You know in Ireland, we have a saying 'you better put those eyes away.' And you know what those eyes are doing to me? "
It then occurs to me that that this exchange has become some sort of transaction, what do you get and what am I supposed to give for a free drink? Is there an etiquette behind it that I'm missing? What are the politics behind it? Is it just a drink for accepting compliments? Bugger, I'm shit at this. Maybe I'm completely misreading this and he really just does want to exchange apple pie recipes.
I'm staring at my gin and tonic, lost in thought when the barmaid slams the money on the counter and stalks off.

I look up and I'm surprised because she's done with it such violence.
He gives me an easy grin "Oh, she's just mad because I slept with her last week. She's just jealous of you."

I almost dropped my fucking glass. I had alcohol and lime all over my hands. What the fuck dude! I didn't need to know that! And thank you for clarifying your intentions because I really needed them crystallised. And also, your hoebagginess is not something you should advertise like that, but thank you for the upfront hoebaggery honesty. No wonder she was frigging upset. Lastly but not leastly, I really didn't want an angry bartender to glass me in the eye for accepting a GnT.

What an expensive drink.

I gave a nervous laugh. Ahaha. And I start to back off onto the dance floor. Thanks for the drink! I'm not sleeping with you for it!

I head back to Dealergirl and mouth 'help.'. She leans into my ear and says 'He says he's going to kiss you before the end of the night.' She's delighted. I have a headache. All I wanted was to dance like Run DMC.