This fantasy is inspired by a few videos I have found. The scene is a stripper performance. There are a bunch of them on www.pornmd.com with some really hot (and a few not so hot) ladies at European sex and porn festivals.
There is one in Barcelona that recurs. Has a few performances by the likes of Katya Sambuca and Tarra White that are worth a watch or two or three.
Anyhow, a regular theme of the shows (sometimes - far from all the time) is the "invite the guy from the audience on stage, put him in a chair and tease the tar out of him".
However, I have never seen this "taken to completion" - That is my fantasy that is extremely unlikely to happen.
Here I am, unsuspecting guy at the club, tipping her on stage. She invites me up onto the stage to assist in entertaining the crowd, gets a bit "carried away" and does all kinds of great things to me up there. There is a BJ at a minimum, maybe more than one.
Anyhow - it aint gonna happen, right? But I would happily watch a link or two or three where it did happen. I have looked and looked - have not found! But it was a lot of fun looking!
I could see a porn star staging this in a situation where it was Ok doing it all right on stage (like those European shows). The guy would not really come from the crowd as a random choice of the lady - safe practices blockade that. But she could make it look that way - just plant the guy in the crowd, bring up on up, and have her way with him.