We were in our friends hot tub with the hosts and another couple -- all of us were naked and were relaxing after going downtown to the Labor Day fireworks - after a while, the host chimes in "Ok, everybody grab a room and meet back here!"
So, my wife and I went upstairs to a guest bedroom, the hosts when to their room and the third couple stayed out on the porch and got down to business..... it was the closest thing we've had to a soft swinging experience and was a great, erotic experience! (The hosts mentioned after the fact that they peeked in on the two out on the porch before they finished!)

Unfortunately, they have sold the hot tub, but as things settle down, we may have to try something like that again!