My sister, Jean, was widowed a year before these events. She lived about 30 miles from me. I am Andrew (Andy, my sister called me) and I divorced my wife two years before this. I had remained single since then and masturbated when necessary.

Jean and her late husband and I and my ex-wife had been campers. On one of my visits to Jean we arranged to go camping in Scotland. I had been told where there was a nice beach. I would take my small tent and camping gear which included a two burner plate. She would take her small tent and food for a couple of days.

To go to Scotland I used my car and collected Jean at her house and put her gear into the car with mine. When we arrived in Scotland we found that there was a grassy area at the top of the beach I had been told about where we could pitch our tents and there was a stream nearby for water. Jean did the cooking for our supper and we bedded down in our tents for the night.

The following morning we walked to the beach on our bathing costumes, Jean in a two-piece costume an I in trunks which had an elasticated waist. We paddled in the shallows and found the water was rather chilly. Jean said that her swim would be a short one and I said mine would be, too. I dived into a pretty large wave and to my horror my trunks slid right off me from the force of the wave. I tried to catch them but failed.

There I was, stark naked, not far from my sister so I was in a quandary. If I stayed in the water I would get very cold but if I ran out to get my towel she would almost certainly see I was naked. I decided that I could get out of the water by swimming to the shallows and run to my towel, which I did, but was not quick enough because Jean came out of the water at the same time as me. She walked to her towel as I ran to mine.

I wrapped my towel round my waist to hide my nakedness. Jean picked her towel up and dried her back and shoulders.Then, to my surprise, she peeled off her bra and keeping her breasts covered, dried them. The next thing she did was to slip out of her trunks to dry that part of her which left her breasts exposed to me. Although she was in her late thirties, as I was, I saw that her breasts were firm.

"You`re staring, Andy" she said.

"Yes, I am. I can`t help it. It`s affecting me a little".

"You`ll be even more affected because I`m going to lie on my towel to let the sun finish drying me off.

I`ll be naked but don`t worry because I`ve just seen you in that state so here goes".

She put her towel on the sand and lay on it. She had a lovely figure and I could see her pussy was shaven. Seeing her completely naked like that made my cock grow a little more. As she was naked there was only one thing for me to do. I put my towel on the sand and lay beside her.

"My word" she said. "You have been affected. It`s grown somewhat. What does it look like when it`s right up? I`d like to know".

"I don`t think you should see it like that".
 
"Why not? I`d like to get it right up to see it"

"All right then, if you really must".

She held my cock for a while which I confess I liked very much. Then, quite deliberately, she stroked me. When it was fully up I told her that she mustn`t continue or I would cum.

"Don`t you want to cum?" she asked.

"Of course I do. I don`t think I can hold out much longer. But what about you? Would you like me to make you cum as you do me?"

"Yes. I`m getting quite worked up seeing you naked and doing this to you".

I pushed my fingers into her cunt. It was rather wet in there so I knew that she was somewhat excited. We masturbated each other and my cum shot out on to my stomach. She writhed and panted as she came. I was delighted at what she had done to me and I reckoned I had given her pleasure, too.

"I really wanted you to fuck me, Andy".

"I wanted to to that, too, but we mustn`t"

The next day we went in my car to a nearby village to do some shopping. When there, Jean asked me to wait in the car while she went into the chemists to get some anti midge cream for us to put on the exposed parts of our bodies. We had been pestered by them the day before.

When we returned to our tents we walked, naked, to the sea and had a swim. We lay on our towels when we came out. Jean and I masturbated each other again. I said what a pity we couldn`d have sex.

"We can, Andy. When I was in the chemists I also bought some condoms. We can fuck as often as we want".

I fucked my sister several times until we had to return to our homes. Whenever we went to each other`s house we fucked until we both of us found new partners and re-married. Neither of us will ever tell our spouses that my sister and I had fucked each other, of course.