That is having sex with your own partner (and not swapping) with another couple in the same room.
Me and DH are curious and find it erotic. Looked at a UK swingers site and saw adverts full of people with their bits out and faces on display. We're interested but are worried about how unsubtle some of these people appear to be.
Has anyone had any experience of mild swinging like this or could it be a ghastly mistake and find yourself in the company of some over eager couple ?