As the youngest by far of five brothers I have never been shy about nudity or masturbation. My eldest brother left home when I was young but the others all remained at home well into their twenties and early thirties. The youngest of my brothers was in his early twenties when I reached the age of 12 and it was then that we discussed masturbation and he showed me how to do it. After that I occasionally saw him and my third eldest brother jerking off and I was really turned on by their adult cocks and the spurts of cum which they could produce. I began to practice frequently to copy my brothers actions causing dry orgasms and after a few months I got up the courage and discussed with a couple of good friends what I had learned. The first friend Stephen was a few months younger than me and like me had not started puberty so I told him what I knew and showed him and he stripped off and copied me. We were both surprised to find that despite being equally hairless as me his dick was twice the length of mine and he was very good looking so I really enjoyed wanking with him and helping him get his first dry orgasm.
Then I discussed the subject with my friend Gareth who was a year or so older than me and very fully into puberty. He told me he jerked off all the time and that he could spunk so I begged him to let me see. We both stripped off and I was amazed and excited by the size of his cock, which was larger than either of my brothers' even then. I told him so and he was very proud, he informed me it was 6 inches long and proved it with a ruler from my desk which he then got me to use to measure my own which was 1 1/2 inches, a quarter of his size! As we each played with our own very different cocks I kept commenting on his fantastic, big cock and he finally said I could wank it for him if I wanted. I leapt at the chance and was soon jerking his long, and very fat shaft as he used two fingers to rub my little stiffy for me. After a few more minutes he groaned that he was going to cum and I felt his thick tool throb in my hand before shooting about 8 jets of hot spunk out covering his neck, chest and stomach. I quickly let go of his still throbbing cock to delve my hands into his warm jizz and rub it over his body and over my own.
I couldn't wait to tell Stephen about my encounter with Gareth; he was clearly turned on by it as he then got his dick out and said for me to jerk his dick for him, which I did with pleasure. We arranged for a sleepover at my house where we soon were all naked and Gareth was letting me jerk his big cock for him while Stephen watched, jerking his 3-incher. When Gareth shot his load Stephen was REALLY amazed as he had never seen cum before. I then jerked Stephen while he played with me and we both had dry climaxes before Gareth got another hard on and asked me to give him another hand job. I eagerly did as he asked and this time I knelt down and wanked him while Stephen watched giggling. When he came his spunk shot out in my face and down my chest and stomach.
The following week when I went to Gareth's house it was clear straight away that he had told his sisters about what we had done as they whispered to each other and giggled as I walked in. This lead to further adventures.