My wife and I had been away for a few night and were on our way home. Then Daisy insisted I find a toilet. I was annoyed with her. How many times had she done this to me. The only ones I knew of were at a pull in off the A40. I told her she would have to hold it for a while longer. The minute that we got there and I had pulled in and stopped she was out the car and dashing for the toilets. There were a few lorries parked up and two other cars with a few men wandering around. I sat there waiting. She seemed to be taking an awful long time for a wee. Perhaps it wasn't just a wee. She had been gone for almost fifteen minutes when I decided to see if she was alright. The entrance to the ladies was the other side of the building, so I wandered around there. There was nobody outside so I put my head in the door and called out for her. No reply. I called again. Still no reply. After the third call and no reply I went in half expecting to find her in some sort of trouble. It was pitch black in there as none of the lights were working. By the light on my cell phone I checked the stall to find she wasn't there in any of them. Fearing she had been kidnapped or something I rushed back to the car. There she was stood by the car that I had locked. Was I relieved that she was ok. I let her in and was also soon seated myself and pulling away. We were a little further down the road when suddenly Daisy said, "That was the sexiest thing you have done in ages." I was totally confused and said what did she mean. "Sneaking into the ladies and fucking me," she replied. I had to pull over and stop the car. "What the hell do you mean?" I asked. She repeated that I had come into the ladies and fucked her. I asked what happened and this is what she told me. "I was sat on the loo and a little bit of light came in as you came into the loos You seemed to be looking for me in each stool until you found me in the third stool. You held my head and stuck your cock in my mouth. I sucked you for a few minutes and then you started to leave. Then as I had finished weeing I stood and dried myself with the paper from my pocket." She always carries toilet paper in her pocket. "Then before I had a chance to pull my panties back up, you bent me over resting on the cistern and fucked me from behind. Then as I dried myself again you left and I assume you went to the gents." It was now that I informed Daisy that It wasn't me that had fucked her. For a few seconds she looked at me as if to say your kidding me and then she realized that I was serious that I hadn't fucked her. We had been into swapping for quite a while, but this was the first time that she had been screwed by someone anonymously. "Find somewhere and fuck me," she insisted. I knew of a quiet lane about five miles further on and we were soon in the back seat fucking like teenagers. To say her adventure had excited her was an understatement. I don't know about Daisy but it was my best fuck in a very long while. Again when we had finished and driven another hour home, Daisy was still excited and dragged me straight to bed. She wanted me to fuck her bent over like the anonymous man had. We got to call him the invisible man after that. I only have to mention the invisible man and it gets Daisy's panties wet every time. Since then Daisy has had me pull into those toilets every time we pass them. It has never happened again, but I know that Daisy would be more than happy for it to happen again. Me, if it gets her that wet and excited I would be pleased for it to happen again. I have been thinking of how I can engineer something similar again for her.... and me of course.