This isn't exactly swinging but it was fun though... Last week it was really windy round here. I noticed my neighbour had her washing, including some lingerie out on the line. As I was watching all her pretty bras and panties a huge gust of wind came up and a white item flew off the line and into my garden. I went out to see what it was and discovered it to be a pair of panties. They were really nice, having a full silky back and a semi-see-thru, lacy front. Holding the fine delicate treats I was hard in a second.
I don't wear them myself but always keep a few pairs of nylon panties around for when I'm jerking-off. Now, my neighbour is a pretty woman, about ten years younger than me but married. I thought it could have been fun just to knock on her door and give them back to her. But my cock had other plans.
So I went straight to my bedroom and stripped naked. I drifted her panties all over my body before wrapping the shiny nylon and lace layers around my cock. I fantasised about my neighbour while stroking myself and, after holding out for a long time, eventually blew a huge load of cum inside her panties. I ran them under a cold tap to disperse the worst of my goo but when they dried I could see there were still tell-tale signs of my cum on them.
That evening I noticed her washing was still out. I knew she worked shifts and wouldn't be home until later. The wind had died down so I just hung the soiled panties on the fence. Next morning I waited and watched behind my net curtains as I saw her bring her washing in. She retrieved the cum-stained panties from the fence, as far as I know, none the wiser how they had got there. I jerked myself off into one of my pantie collection soon after that.
Later in the morning I saw her hanging out another load of washing so went into my garden on the pretence of doing some weeding. We just said a quick hello over the fence and I noticed the same panties were on the line again. Her mood seemed pleasant enough so I'm sure she didn't suspect me of any wrong-doing. Perhaps she just thought her panties had picked up their stains from being caught on the fence overnight.
Even so I went back indoors and had another glorious panty-wank as I relived my dirty little secret. Hope it happens again soon.