It was a very hot day and it was going to be another hot night. There was no chance that I was going to be able to sleep so I suggester to Lizzie that we went down by the river and walked the banks where it might be a little cooler and try to wear ourselves out ready for sleep. Issy agreed and after settling our dog and seeing she was ok we locked up and I drove to the river. Once parked, we started to walk the well trodden path. We soon came across another couple who had gone several steps further than us in that they were in the river and frolicking in the cool water. It was quite evident that the woman wasn't wearing a bikini top as her tits, which was quite sizeable, kept coming into view. She made no effort to hide them and as we got closer the man engaged us in conversation. It obviously started with the heat and moved to how nice and cool it was in the river. We stopped talking and I was enjoying the view of Fiona's tits as they bobbed in the water. She was sat in the water that was just about nipple height. Fiona suggested that we joined them and cooled off. I said that we didn't have any costumes and Fiona quickly replied that neither did they and with that she stood up exposing herself. The first thing I noted was that the collars and cuffs all matched and she was a true redhead. Ken her partner, not to be outdone, also stood and I heard a gasp from Lizzy. I thought I was reasonably well blessed with a fairly thick seven inch cock, but I was out gunned by Ken who was about the same length but definitely thicker and it was soft and floppy. Again Fiona invited us to join them. I was about to say no thanks when Issy was pulling her dress over her head. I already knew she wasn't wearing a bra as she had stopped when this heatwave started, but what I wasn't prepared for was that as the dress came up she also wasn't wearing panties. With a quick flick from her feet, her shoes shot off and she was totally naked and getting in the river. Fiona called out to me to hurry up as I would be missing all the fun. I was a bit apprehensive as the only times I had got naked, in a public space, was in the sand dunes with a couple of old girlfriends at various times, and now this is somewhere much more public with a greater chance of getting caught and with complete strangers. With pressure from all three I slowly removed my shirt and shoes. Ken teased that perhaps I was embarrassed about what was between my legs. I assured him I had nothing to be embarrassed about and quickly took my trousers and pants down to show them. Fiona commented that I was right that I was well blessed and had nothing to me shy about. Then I was quickly in the water and sat to hide my cock. Lizzy sat as did Ken, but Fiona remained standing which meant that her pussy was head height and I had a very clear view of her pussy and the red patch of fur just above it. Ken saw me looking at Fiona's pussy and said, "Nice aint it." I nodded in agreement. We frolicked in the water slashing our partners for a while and then splashing each others partners. Ken suggested that we all went for a swim. I looked confused as I thought the river was no deeper than a few feet. But I was soon put right that there was a deep pool about thirty feet further down. The four of us started to wade our way towards the deep pool and Fiona stumbled and I caught her from going over. The thing was that in catching her I had an arm around her and a handful of tits. Ken laughed, "He's only know us two minutes and he's already fondling my wife the lucky sod." I immediately went red in the face. I could see a smile on Lizzy's face as she knew it was not a sexual grab but one to rescue her, but she also knew that I had probably enjoyed it anyway. Once at the deep pool, it was deep, it stepped at about five feet three feet in and then dropped well over my six feet one inch height nearer the center. In all the years that I had lived and played in this river I never knew it had deep areas. We were frolicking again and trying to splash and push the women under the water. Ken had just picked Lizzy up and threw her quite a distance and she fell and went well under the water. She was soon back up and trying to get her own back on Ken. I had grabbed Fiona and was trying to throw her, but to prevent me she grabbed my cock. I told her that was cheating and I'd give her six weeks to stop that. I managed to pull her off me and managed to throw her. For several seconds I couldn't see where she had gone and then a mouth sucked my cock into it and sucked hard as hands pulled my arse towards the mouth. As I had thrown Fiona she had turned the second she touched the water and swam back underwater and was now sucking my rapidly growing cock. Ken saw what Fiona was doing and called out that Fiona never played fair. She had now stopped sucking and was coming up for air. Lissy had also seen what Fiona was doing and looked miffed. I don't think the smile on my face helped any. Then she dived under the water and it was Ken's turn to first look startled and then develop a big grin. Lizzy was sucking Ken's cock. As far as one can know, I believed that Lizzy had never cheated on me and now she was sucking a strangers cock underwater. Then she was also coming up for air. The two women were looking at each other. It was almost like a standoff. Fiona went first and dived back down and re-attached her mouth on my cock. Lizzy hit the water a fraction of a second later and I could see that smile on Ken's face return and develop into a big broad grin. This time I tried to count how long Fiona was down and it was nearly thirty seconds. Fiona lasted almost fifteen seconds longer. I dived under the water and tried to see if it was possible to lick a pussy underwater. I wasn't that successful and after two quick licks I was on my way back up. Ken followed my lead and as I hit the surface I heard Lizzy squeal as ken obviously found her nub. He managed almost a minute and to follow her squeal Lizzy gave out a groan before Ken returned to the surface. I wondered if she had come as it's the only time she groans quite like that. Then there was lot more splashing before we had a real swim. I swam behind Fiona so I could see her arse and pussy in the water. There was too much splashing and I couldn't see much, mores the pitty. After the swim we made our way back to the shallow area near our clothes. I suddenly realized that we didn't have towels and would have to dress and go home wet. Fiona and Ken had and as we got out Ken started to towel Lizzy off and Fiona followed by toweling me. By this time I had quite a boner, and Fiona took far more time than needed to dry my cock. Ken was also lingering as he dried Lizzy's pussy, mind you, he could be there a life time as she is always wet down there. Then we swapped over and I was drying Fiona and Lizzy was drying Ken. After she had dried him and was wiping his cock again she shocked me by taking it into her mouth again. Somehow this felt far more sexual than when we were in the water. Not to be outdone I suddenly found Fiona clamped onto my cock again and sucking like a champion. This lasted a good five minutes before Lizzy pulled away, and I watched as she turned and bent forward, offering her arse and pussy to Ken. I'm not sure if she had expected Ken to lick and suck her pussy but he took one step forward and stuffed his large hard cock straight into Lizzy's pussy. Lizzy was groaning with every thrust ken made. Fiona must have heard Lizzy and looked to see what was happening. On seeing her partner fucking my wife she also put herself in the same bent over position and I didn't disappoint her and slipped my cock straight into her tight pussy. I was a bit surprised having seen the size of Ken's cock that Fiona pussy was so tight. I was soon matching Ken's rhythm and plowing into Fiona hard and fast. As they started first, Ken and Lizzy finished first with ken bellowing his pleasure as he dumped his cum into Lizzy. I was getting close and Ken suddenly shouted to me not to come in Fiona as she isn't on any protection. I was a bit annoyed to have to pull out when he had just blasted his cum into my wife's pussy not knowing if it was safe to do so, but he wanted me to pull out. I did pull out but I wasn't happy about it and I don't think Fiona was that impressed either. We all finished dressing and Lizzy suggested that we all went to the pub about 300 yards off the footpath. In the pub we started to talk about general things, but Ken soon turned that topic back to sex and what had happened earlier. He complimented Lizzy for being such a good sport and an even better shag. I told Fiona that I had enjoyed my time with her and she said that we should do it again soon. Ken and Lizzy agreed. It turned into a regular thing and on the second occasion I learnt that Fiona was not Kens wife. In fact both Ken and Fiona were married but to two other people, and neither knew of their clandestine meetings. Here was Ken loaning me someone else's wife. No wonder he didn't want to risk her getting pregnant. What Fiona hadn't told Ken was that she was on the pill and quite safe, so the second time we shagged I went all the way on the two occasions that we fucked that night. We met another four times after that, and on each occasions I left my load deep inside Fiona's pussy. The next time we saw Ken he was looking pretty beat up. It transpired that the last load I left in Fiona was discovered by her husband. He followed Fiona the next time she went to meat up with Ken. It was then that Ken took a beating. I felt it was ironic that he took the beating for my cum when the first time when he came in Lizzy he wouldn't let me cum in Fiona, now when I did he took a beating. Lizzy saw Ken once more after that, and I was unhappy, as she had done it behind my back. It was one thing to go swapping as a couple but another thing to go solo. We never met up with Ken again, but as Lizzy and I now had a taste for swapping we went on to meet other couples. That was fourteen years ago and we continued swapping up to the Pandemic. Hopefully we will be able to resume our extra marital fun again soon.