It was Saturday. One of those hot, humid days. No wind, as uncomfortable outside as it was indoors, but we opted for outdoors anyway. A few miles from our home is a navigable river, now used only by occasional adventurous narrowboaters. It's a favourite summer haunt of ours. It has a good path, mostly overhung by mature trees. The only problem is that access to it on foot, is in built up areas, so it gets busy, especially at weekends. Of course, the further you walk, the quieter it gets and today was not a walking day anyway, much too hot. However, I had discovered a footpath that joined it about halfway along. We would try it. We took a picnic, intending just to get to the riverbank and spend the day lazing in the shade. I had located the non-river end of the path on a recce, it looked like it crossed a field then disappeared into a hedge on the far side, but the OS Explorer showed a twisting path to the river. There was a place to park about two hundred metres away. When we got there, there was a car already parked, but we payed little attention. We crossed the field, passed through the hedge and found the path, narrow and overgrown. We picked our way through the nettles me leading the way, until the path widened. The path zig-zagged round the corner of fields surrounded by high hedges. As I turned a corner, I was confronted by a man, pants round his ankles and a woman on her knees, sucking his cock. I stopped dead. He turned to look at me, the woman just continued sucking. "Sorry," I stammered. "We'll just…" Just what? Turn around a let them get on with it I suppose. Bang goes our picnic. Heather, my wife, had been few yards behind me, she caught up. "Oh!" She squealed. The man spoke; "It's alright, we don't mind an audience." The woman, whoo had not missed a stroke, turned her head slightly. She was blonde, with pale blue eyes. Her pretty face distorted, mouth stretched by the man's girth. I looked at Heather, she could not take her eyes off the scene. The man took hold of the womans head, grunted and closed his eyes as he emptied his balls down her throat. I could see her throat move as she gulped down his offering. She released him, and looked up at me, there was spunk on her lips and chin. She licked her lips, smiled at me and said; "Hi, I'm Jill, this is Tony." I apologised again for interupting them. 'Tony', who had by now adjusted his clothing, said; "Not at all, we should apologise to you." Jill chipped in; "We were on our way down to the river, you don't get many walkers that far from civilisation, even fewer here. We usually fuck on the bank, so that we can be seen from the boats, but Tony was impatient today." Tony picked up a small rucsac and headed in the direction we had been going. Jill followed him. I hung back and asked Heather if she wanted to continue, or to go back. She was intrigued. We continued. Our path joined the riverside path, towpath I suppose, near a bend in the river, our new friends turned left, Jill asked if we would like to join them. Heather nodded. The spot they chose was perfect, right on the apex of the bend, with a clear view along the path in both directions. They too, had brought a picnic. We chatted as we ate. They were about our age. We each had brought wine and Heather tends to lose her inhibitions after a glass or two. "Tell us about this exhibitionism thing." She slurred. Jill explained; "Nothing much to tell really, we were once caught 'in flagrante' in a corn field, Tony was on the short strokes, we just carried on. The walker, a woman on our own, just hurried away. We were both turned on by the experience and started to engineer circumstances where we knew we miight be seen." Tony added; "Do you know what dogging is?" I nodded. "We do that too, just to be watched, we don't allow others to join us." I could tell that Heather was becoming aroused, her nipples were making little tents in her T shirt. I had a hard-on and shifted it to a more comfortable position. Heather and I were not exactly averse to an al fresco frolic ourselves, but had never been watched. Not to our knowledge anyway. Tony put his arm around Jill and cupped a tit, within seconds, they were locked in an embrace. Jill fished out Tony's cock, clearly fully recovered, and began wanking him. He told her to get on her knees, pulled her jeans down and slipped his cock into her. Heather gave me a questioning look, I nodded. She unzipped me, took out my hard meat and took it into her mouth. She sucked me off as I watched our new friends fuck. We were not interupted by either walkers or boaters. We fucked like snakes that night, very turned on by the day's events. We have since joined Jill and Tony for open air foursomes, no swapping, just with our own partners. Next week, they have promised to take us dogging.