Prague swinger clubs - anyone with any experience?

This is quite complicated. We enjoy threesomes and even small gangbangs, but provided I and my wife have full control over what's happening. I'm always at her side (though I know couples that find thrill in splitting in the club and then telling each other their adventures), so I want them to ask me first, if they can penetrate. It gets on my nerves, when they know I'm controlling and start putting on condoms, thinking they'd just do whatever we want. But from the last time we've learned our lesson. No more accidental actions. If we desire a gangbang, we will choose a few guys and go with them to a separate room.