My girlfriend and I visited a BDSM club in NYC a couple of years ago. There were maybe 100 people there when we arrived around 1:00am. Most of the occupants were single men who walked around openly masturbating themselves. A few couples. An occasional small group of women would come and go. While sitting at the bar, on more than one occasion men would ask my girlfriend if they could lick her feet while they played with themselves. She didn't mind and I never cared. It's an interesting experience making small talk with your girlfriend while someone is sucking her toes and jerking himself.
From time to time a 'scene' would develop usually around a woman or a couple playing with each other. A group of ten to fifteen guys jerking their dicks would quickly close in on the scene and jockey for position to see what was going on. It was always difficult to get in close enough to see what was happening so I rarely visited these scenes.
About two hours after we arrived a scene had dissipated and I saw that the center of attention had been a semi-nude (naked on top with bikini underwear on below) woman sitting in a chair. There were still a couple of guys standing around but I wandered over there to see what was going on. One guy was stroking himself in front of her. Another sat behind her and massaged her tits. She was on a chair but in a semi-reclined position. Another guy, who was in control of the scene sat in a tall chair while watching the proceedings. I pulled out my dick and began stroking. There were now maybe four guys including myself all stroking directly in front of her. She lazily stroked one of the guys. Since I had been stroking on and off for about two hours I didn't feel like waiting much longer. I asked the guy controlling the scene if there were any rules. 'Don't come on her face'. Ok. I stroked for another 30 seconds or so and let loose with the most intense orgasm and ejaculation I had ever had. I shot about five huge streams of come right on the woman's chest and she began moaning. The guy behind her massaged my come all over her tits. People actually applauded.
My girlfriend had remained at the bar and missed it. We went back on several occasions and had several other mostly masturbation experiences.