I had been badly injured whilst serving in the Army abroad, and after a lenthy recovery I was back at my unit, but on Light duties, as I did not have full mobility at that time. My old army mate Paul, who had left about 2 years ago offered to pick me up and take him back to their place for the weekend. His wife Carol and him and myself had serverd in several bases over the years, so I knew her pretty well. A nice surprise awaited me on our arrival back, Carols Twin sister Nikki, was also there, i had met her a couple of times in the past, funny one of the things to tell them apart was that Carol had a obvious Birth mark on her thigh, and Nikki did not. but you could only see if if she was wearing her bikini. After a nice meal and a lot of chat, I headed of to bed, and after a wash up, climbed naked into my pit. A little later when I was just driffting off, the door opened and the deuvet was pulled back, and a very naked body pressed up against mine, and her hand found my cock, she whispered, I take it you will not mind some company for the night,, Thinking I had fancied Nikki in the past I was not saying no. We started kissing fingering and finally my cock was deep inside a very wet and warm pussy, and we fucked. I managed a couple of more times without the intensity of the first time, and fell asleep with her wrapped in my shoulders. Morning came with sunlight outside, the bed covers was off and I had a massive hard on with her sucking deeply at my cock, the door opened and in walked a naked Carol followed by Paul. she pulled the curtains back, to revel herself fully and I had a double take it was Not carol, but Nikki standing ther, Carol was still holding my cock, and rubbing her hand up and down it. I had been fucking carol all the night thinking it was Nikki, Mind from the sound from the other bedroom a couple of ties during the night Paul and Nikki had not playing footsy. Nikki came over to me grinning, and took my cock in her hand, whilst Carol took hold of Paul's and wanked him into a hard on. she lay back and I watched as he slid his cock into his wife's pussy where not that long ago I had been. Nikki came on top of me and slid down over my hardened member. and we also fucked with Paul and Nikki fucking beside us. later the girls explained that when carol had first started seening paul, the girls swapped over so he on a few occassions fucked Nikki, thinking it was carol. untill he found out about the biirth mark. and from then of the had often swapped about, and thought it would be a treat for me. that Night we we went to bed I made sure it was Nikki I was fucking with as I looked for the mark, ha ha. couple of more weekends with the four of us, certainly helped in my recovery somewhat. One afternoon, a few weeks later and we where all lieing in the back garden naked soaking up the sun, when suddenly from the hedge a couple walked through, Nikki was next to me, and holding my cock, wich was at half mast as it was hot, and I still got tired quickly. Carol stood up, and did not seem bothered that she like us had not cloths on, Quickly she introduced there neighbours Ted and Paula, who in seconds had soon stripped of, both in there early forties, I guessed, and she had a complety shaven area at the top of her legs. Paul had brought some drinks out and after a couple, I could not have much as it affected the medication I had to have, Carol and Paul had obviously told them about me, and we all soon relaxed, Nikki started to run her hand up and down my cock ance more, suddenly Carol started to do the same with Ted and Paula, came over to me and said could she take over, suddenly it seemed her and I were kissing and my fingers were playing inside a very wet hole Nikki was sucking Paul and Ted had his cock inside carol, and soon mine was inside Paula's. Very unexpected very enjoyable and definate wow factor.. Paula told me her and Ted had went to a swingers club, and suddely found Paul with a massive hard on being sucked of by some women and Carol was ther being fucked by the womans hasband, after the usual what are you doing here session, they later had a foursome together, and quite often swapped over in there respective house from time to time. Nikki and I have started seeing one another a lot more and are talking about getting a pad together, and we still visit Carol and Paul for a swap, and even make it with Paula and Ted, now and again.