A few years ago my girlfriend and I went for a drive to the coast. We left early in the day with the idea of getting some lunch somewhere nice then driving back to the city. However, as we drove the weather got better and better and turned into a fabulous day to sunbathe. We hadn't brought any swimwear but we both had quite brightly colored underwear so we thought that we could get away with stripping down to our knickers as long as it was a private part of the beach.
We found a nice sheltered spot, spread out a rug and lay down to enjoy the sun. After a while my girlfriend asked if I would top up her sun tan. I was quite keen to do this as I was starting to get quite horny and really felt like touching her. I started with her shoulders and arms, then her back. As I did her back, I explored under her arms and touched the sides of her breasts with my fingertips. She gave a lovely 'mmmm' and turned a little so that I could touch more of her breast. I slipped my fingers down and squeezed her nipple and got a really positive reaction. I thought I should be good and complete the task of applying sun tan lotion, but became distracted again when I got to the top of her legs. Her knickers were lovely and soft and it was quite easy to slip in under the elastic. I massaged her bum for a couple of minutes and then decided to be more adventurous. I slipped my fingers between her cheeks and stroked her anus, this got a great reaction and she pushed her hips up and spread her legs. I was then able to slide my fingers down to her vagina, which by this time was extremely wet and explore down to her clit. My girlfriend had started pinching her nipples and was really enjoying the whole sensation. It was then I noticed a movement out of the corner of my eye and looked up to see a guy sitting further up in the sand hills watching us while openly masturbating. It gave me a huge scare and then I suddenly felt really horny. I started stroking my girlfriend's vagina with more enthusiasm and she shuddered in a sudden climax, squeezing her thighs to control my hand. She lay still for a moment and then wiggled her hips. I started stroking her again and after about a minute she came again with a climax that seemed to shake her whole body. The guy on in the sand hills was stroking as fast as he could and climaxed just after this. He then quickly tucked his penis back into his shorts and left. My girlfriend relaxed back onto the rug with a contented sigh and I lay down next to her with a boner that was nearly killing me.
After about fifteen minutes she suggested that we return to the car and we drove of to look for something to eat. My girlfriend said 'did you see that guy whacking off when I climaxed, I felt like I was in a porn flick'. She said she was still horny and slipped her knickers down and started to softly stroke her vagina, I pointed out that I still hadn't climaxed, and would like to know what the other guy felt like.
I stopped the car and pulled my jeans and undies down and started jerking off while watching her stroke her vagina. We both came almost straight away.