My ex mrs (Debs) loved to flash and tease guys when she was sunbathing in the local dunes. She would often sunbathe nude in our back garden which was not overlooked and very secluded. Debs was 35 yrs old at the time and worked part time, mornings in the local tax office. She had shoulder length auburn hair, brown eyes, nice smile, nice firm tits (34”), flat tummy, firm toned legs and nice firm arse. She would keep her pussy smooth at my request as I hated to get pubes in my mouth when licking her. Flashing and teasing in the dunes started by accident. We both had a day off of work and decided to spend the day sunbathing and chilling in the local dunes. Debs was dressed in loose fitting off the shoulder white tee shirt (no bra) loose fitting short pink floral skirt and sandals. Under her skirt she was wearing a white g string, the small piece of material at the front was very shear and see-through. We packed the beach bags into the boot of the car and off we went. When we got to the dunes it looked to be quite busy by the amount of cars that were there and it was also a school holiday. I managed to find a spot between a couple of cars and parked up. Debs went to the boot to get the bags whilst I took a call on my mobile phone. I was stood at the back of the car whilst Debs was bent over reaching into the boot when a gust of wind from a passing lorry blew her skirt up exposing her bottom, with one hand holding the bags Debs held her skirt down with the other. Ever the gallant gent lol I closed the boot as she made her way onto one of the paths leading into the dunes. As I was closing the boot I noticed that a guy was in the driver’s seat in the car parked behind us, he must have seen Debs when her skirt blew up. I shut the boot and followed Debs into the dunes. We found a nice spot in the dunes out of the wind and I started to set up the towels. Debs was looking through the bags. She told me she couldn’t find her bikini, she can’t have packed it. I told her that it would be ok as she would have gone topless and that she could get sun to her legs as her skirt was quite short, Debs removed her top and started to apply sun lotion to her arms, shoulders, face and tummy I volunteered to do her tits, she laughed calling me a perv and did them herself. Her nipples hardened as she was applying the lotion we then settled down to enjoy the sun Debs seemed to doze off. We had been there for about 15-20 minutes and I thought I would go to the top of the dunes for a look around. When I got to the top I noticed a guy approaching us, as he got closer I recognised him as the guy from the car. I looked down at Debs her skirt had ridden up so that you could quite clearly see the front of her g string which I have to say wasn’t hiding much. The guy was too close now for me to do anything so I pretended to look out to sea. I watched out of the corner of my eye as he stopped and looked down at Debs. He then walked down into the hollow and past Debs, he was very close to her feet and will have seen everything, he then past her and walked further on. I watched as he walked around the dunes and disappeared. I re-joined Debs as a sat down after a short while she turned onto her front and asked me to apply the sun lotion. I started at her shoulders and worked my way down to her waist, her skirt had ridden up and her bottom was fully exposed. Starting at her feet I worked my way up to her peach like bottom working on each buttock and occasionally dipping my fingers into the crack of her arse moving down from her arsehole to her very wet cunt. I inserted a finger between her cunt lips and started to finger her. Whilst fingering her I looked for the lotion bottle to use, as I was doing this I looked up and saw the guy that had passed us watching. I found the bottle and rubbed it onto her cunt, Debs had opened her legs to allow me access. I inserted the bottle into her as I did so I looked up to see that the guy had moved closer and was sat watching. He had opened his trousers and was openly wanking his cock. I pulled the cheeks of her bottom apart so he could see everything, her string was not hiding anything it had become wet with her cunt juice. As I continued to fuck her with the bottle she shuddered and cum groaning out loud that she needed cock. I looked up and the guy had gone. I released my cock from my shorts, climbed between her legs and slipped my cock deep into her cunt and started to fuck her hard and fast, I cum within a few minutes shooting spurt after spurt into her. As my hard on subsided I rolled off of her, spunk was oozing out of her and onto her g string. Debs turned over and sat up asking me what had made me cum so fast, I told her we was being watched, she didn’t say anything. She took off her string as she said due to the mixture of cunt juice and spunk it was uncomfortable. I slipped it into my pocket. Soon after we left the dunes and returned to our car. The guys car was still parked behind us empty he must have still been on the dunes. Debs sat in the car as I put the bags into the boot. Before I closed the boot I hung her g string on the guys wing mirror for him to find. Don’t know what happened to it as we left. On the drive home Debs confessed that she had seen his shadow fall over her when he had past and the thought of him seeing her cunt had turned her on. That was the start of many adventures for Debs in the dunes.