We are stag and vixen couple 42m and 41f with grown up kids and we have been friends with another couple of the same age for long time and they have kids too. We consider them as family friends as our kids grew together and never thought of them in a sextual way. We are going in a camping trip soon without kids and I was talking with my wife about opening up to them and she is reluctant but she always has the fantasy to play with other husband and she believes that he has the same feelings towards her. I think they are open minded and chilled couple if anything go wrong! So my questions are do we go ahead and open up to them in a smooth way and test the water? If so what is the best way to approach it? Please only serious advice this is not for fantasy or jerking Thanks