This story starts five years ago when I was 14 and in middle school. It involves my two brothers, one of whom is two years older than me and the other is about one year younger. By this time in our lives, our parents would let us be at home alone between the time we got back from school and the time dinner came around so we had a lot of alone time.
One day, both of my brothers come into my room after school. My older brother Mark, starts talking, telling me that our younger brother, Billy, who was blushing at the time, just started learning about girls puberty in health class, and that while he knew about boys puberty he had questions about the girls. Mark said that Billy had asked him but he decided I would be a better person to ask. With this comment and the odd grin Mark had on I started to blush along with Billy. Mark said that one of Billy's problems was that he was having difficulty imagining the female reproductive system. In retrospect, this was obviously an instance of my older brother using my younger brother's innocence to gain access to my nude body, but I fell for it. I got along well with my brothers so I was in for a little show of my vagina (I didn't think it would get sexual although I knew it was 'wrong' to do). But, embarrassed, I insisted that I needed to learn about boys and made my older brother agree to show the effects of puberty on boys. When he agreed to do so, I dropped my pants and panties.
Both of my brothers kinda stared and I started to get embarrassed until I glanced at their crotches and realized they both sprouted hard ons. This started to turn me on and got me thinking sexual thoughts for the first time that afternoon.
I said 'Ok show us yours Mark.' He eagerly shoved his pants and boxers down in one swoop to reveal his six inch hard on. Obviously that's nothing big, but as all girls think their first time, I thought it was pretty huge. I saw a wet spot on his head that I later realized was precum. My little brother was amused a little, but it turns out that he had already seen Mark with a naked boner so he was content with looking at my pubescent crotch. Mark then convinced Billy to join our nudity fest so he dropped his pants revealing his hairless four inch boner. Then Billy spoke for the first time and asked if I would show my 'boobies.' I did. So there we were, three naked teens in my bedroom.
At some point in the process Mark had started rubbing his dick which caught my attention. I asked if he was gonna go all the way and cum for us. He said only if I show him how I 'diddle my clit' but this was before I had ever masterbated so I didn't know what to do. I told him and he walked me through the steps. So after a couple of minutes my two brothers were stroking their very different dicks while staring at my boobs and my pussy which I was rubbing for the first time. I soon experienced what I knew had to be an orgasm and both of my brothers followed, but obviously only one shot semen. When he quickly grabbed something to shoot into he grabbed my panties and shot several strings of the first cum I had ever seen into them which I thought was absolutely disgusting. He quickly apologized kinda got red in the face and then left my room with clothes in hand which left me with just my naked little brother. I asked him if he had an educational experience and he said that he did. He then put his clothes back on and left.
The next day, when I got home, my older brother was sitting in the living room jacking off and invited me to join, which I did. Then our little brother walked in on us and he joined too.
We masturbated together almost everyday after school for years. It became just Billy and I after Mark went to college and now that I'm at college it's stopped altogether, except for summers and breaks. When we were younger we would masturbate all summer long together. Hopefully that tradition will be kept in part.