I grew up on a farm many years ago in a rural place. I had a brother a year older and two much younger sisters. Because we were close in age I played a lot with my brother and his two friends who lived near. There were no girls living near so I was a tomboy until I was twelve or so. This involved holding my own with the boys in whatever games we played. I could fight, wrestle, climb and play football. There was no sexual experimentation, that would not have entered our heads at that time. There was however a certain openess about dressing and peeing. For example my brother and I always undressed together before bed and if we had to change clothes after school etc. So I was well acquainted with boys' underpants and often got glimpses of his penis at these times. Neither did we have any shyness about peeing. When we were out playing by ourselves or with his two friends none of us bothered to go back to the house for the toilet. We just found some shelter behind a tree or a wall or a shed. This was how I got to see the penises of my brother's friends. To be fair to them they never showed extreme interest in me when I peed although all of them in their turn at some time or another took a close look at where my pee was coming from.
When my brother and his friends went to secondary school that ended our playing together and our closeness. I never again saw any intimate parts of his friends and my glimpses of my brother were rare as we dressed and undressed in different rooms. It was just as well I suppose because I was about twelve at this time and my changes had started. Up to this time I had not masturbated or knew anything about it. The only thing I had noticed was that when I needed to pee I sometimes held myself with my hand between my legs until I found a private spot. One night when I was about twelve I needed to use the toilet but somebody else was in there. While I was waiting I held myself with my hand and then rushed to pee when the toilet was free. As I peed there was a great feeling of relief but as I sat there I put my hand down and for some reason from nowhere I remembered watching as my brother peed behind the shed in the yard. That led me to think of times I saw his friends doing the same. All this time I was rubbing along my vagina and I was enjoying it. I had to stop because somebody else wanted to come into the toilet. For a few years after that I often masturbated in the toilet after peeing, usually recalling things from when I was younger. Later on when I was about sixteen I got to understand what masturbation was about and then I changed to doing it in bed. But even to this day I still sometimes do it sitting on the toilet.