I was at my best friend's place watching a game with him over the weekend. His wife was out back drinking cocktails and tanning with another friend of hers whom I had never met. I went to grab a few beers from the kitchen and could see them out in the sun, glistening from lotion and sweat. They were maybe 30 feet away and didn't know I was there. They both had mom bods, since they are in their 30s, but looked great in their bikinis, which were the basic type, nothing too skimpy.
The thing about it, though, was that my friend's wife was rubbing one off out there on the deck. She was facing down, on her elbow, ass slightly up, and rubbing her clit inside her bikini. Her friend sat up next to her and fondled her tits through her top and I could hear her a little through the window, saying things like "go girl, get it." Watching her orgasm was about the hottest thing I've ever seen.
I went back down to my buddy and didn't tell him that I had just seen his wife have an orgasm. I'm guessing that his wife has a lez thing going with her friend, but damn, I think constantly about fucking both of them. I can't get that image out of my head.