Organized sex parties - would you go (or have you gone) to them?
I have, a few times, but never strictly a sex party only. They all were in conjunction with a gay naturist (nudist) club to which I belonged for a couple of years. When we'd have a gathering of a couple dozen guys at someone's private residence, as opposed to a health spa, bar or other public place that was temporarily closed for us, we might have a sex house party afterwards.
But never during the official meeting, which ran until about 10 PM. Then if our host the house owner invited us to stay after the event formally concluded, as his personal guests, no longer a function of the club, we knew that meant sex for all who remained. And not all did.
That's what happened at my very first meeting. By 10:10 PM there was a mass of naked guys all over the place, getting fucked on the floor, on the sofas, everywhere. All with towels under us, since naturist etiquette is to always bring one for yourself, never sitting or laying with bare skin touching objects.
I got lucky, the guy who really interested me hitting on me, and we got it on. It was kinda exciting to see all these other naked guys around us, fucking like bunnies. We kept it simple, just the 2 of us, no 3-ways. In fact, in subsequent visits to that city I always stayed with him and slept in his bed, and whenever we had a sex after-party at one of these gatherings, I always paired with him.