About 5 years ago, when we were in college, my now-wife, then-girlfriend, used to love to turn me on by showing off. After we got married, we kinda settled down (although we stayed "mildly" in the lifestyle), but back then she was pretty wild.
The farther she went, the more I loved it. The more I loved it, the farther she went. At one point, we went through a "phase" where we'd go out every Friday night, and I'd watch her flirt with other guys at the bar.
Her thing was to get them to hit on her, and then offer them a blow job in the men's room. But she set this condition that she had do it topless, out in the open so that any other guy who comes in , could see her in action. If the guy didn't agree, she'd refuse to give him the promised BJ. This only happened once but it was fun!
The reason for her "rules" of course, was because her whole purpose for giving the BJ in the first place, was to show off FOR ME. It was our arrangement. Whenever I saw her enter the men's room, I would wait a half-minute or so, and then go in. I’d stroke myself while watching, until I shot my load. What was most exciting was when others would come in and see me watching them.
I still masturbate sometimes to the memory of those Friday nights.