We have been married for forty years and apart from a drunken wife-swap party many years ago we have been boringly faithful. As would be expected after all these years, sex has become infrequent although my wife has indicated that she would be prepared to try anything that might invigorate our sex life. We have discussed online swinging sites but have never got round to it. Just recently I was in the town and whilst using the public toilet I found a note on the floor which on the first glance appeared to be from a young lad who was asking if someone would let him have sex sex with their wife. I thought this was a joke as the toilets are cleaned regularly so I knew it must have been left there recently. On the spur of a moment I rang the number and was suprised when it rang in an adjacent cubicle. I left the toilet and waited outside and after several minutes a young lad of about nineteen came out. I walked over and showed him the note and after initial embarrassment he admitted it was his. I asked him if he was serious and he said he was, and although he had attempted sex with a girlfriend he was so well endowed it hadn't worked and that was why he wanted to try a more mature and experienced woman. He said his name was Mark and I explained my position and said I would discuss it with my wife. As I was intrigued as to how he could be 'too large' I asked him to show me his cock. We re-entered the toilet and I found out it was true as he had a very large uncut cock which on both counts would more than satisfy my wife. On returning home I showed my wife the note and after an initial refusal she came around and said that I should arrange a meeting but it would have to be at a neutral venue. I rang Mark and we arranged to meet at a local hotel and I would book a room. On the arranged date we went to the hotel and my wife had a bath and a few drinks but I could tell that she was very nervous and more than once she suggested calling it off. I said that she should at least meet Mark and then take it from there. At the arranged time Mark arrived and I could tell that he was also nervous and I didn't know how the age difference would affect the possible relationship. As I felt my presence was getting in the way I said I was going to the bar to get a bottle of wine and I left them to it. On my return twenty minutes later I was suprised to see them both naked and that Mark had his head between my wife's legs. His cock was now fully erect and was very long and thick with the foreskin half covering the leaking glans. My wife hardly noticed my presence and I could tell that she was in the throes of an orgasm. After catching her breath she asked Mark to fuck her but his inexperience now showed as he was having difficulty getting his cock into her vagina. I quickly stripped off and climbed onto the bed and guided his cock into her waiting hole. His size meant there was still a difficulty but he eventually managed to get if fully inserted. He now commenced a piston like motion and as he was so tight each time he pulled out he pushed a small amount of air into he vagina on reentry. This resulted in a number of fanny farts which only added to the erotic experience. After about ten minutes Mark said he was near to cuming and asked it he should pull out,my wife said she wanted him to cum in her vagina. She asked him to let her get into her favourite position (on her knees) and this also allowed Mark to get maximum penetration. It was very erotic watching Mark as he approached my wife from behind and I marvelled at how she could take such a massive cock. They were both now approaching their orgasm and as my wife cried out Mark went into convulsions as he exploded into her. I could see his arse muscles contract as he came and from the leakage around her vagina I knew he must have pumped a large quantity of his seed into her. She asked me to get a towel and place it under her and it was just as well as when Mark pulled his cock out a massive amount of cum ran down her legs and onto the towel. My wife asked if I had enjoyed it and seeing my erection she said that I could have sloppy seconds. I pushed into her but because of her enlarged hole I could not feel anything so I ended up having a wank, much to my wife and Marks amusement. We have met Mark a number of times since and my wife states that her one regret was that she didn't try this sooner.