I went to co-ed sleepovers. Nothing sexual ever happened. And these occurred within two different circles of friends. It was just a bunch of kids hanging out, staying up late, watching movies, eating junk food. At one that I went to, the parents stayed up through the night checking in on us. They weren't all in our business or anything, but with a bunch of kids hanging out in one big room, it's not like there was much privacy anyway to GIO if any of us were even interested in such a thing. In the other sleepovers, there wasn't much supervision, if any, from parents at all. And nobody was doing it!
Sorry, the idea of it makes me laugh. And when it comes to games like truth or dare, or 5 minutes in the closet, it was all a joke. We were all friends, some even with cute, awkward flirtations, and nobody was going to embarrass themselves by even kissing in front of everyone else. And when we did 5 minutes in the closet (well the bathroom) whoever we were paired up with, we'd just talk and joke around and make occasional sex-noises for the benefit of everyone listening.
Those were such great times! I haven't thought about those parties for such a long time. Thanks for the trip down memory lane!