I have been jacking off regularly since I was about 13, and when I was 16 I was still a virgin and have never jacked off with anyone before. I always fantasized about jacking off with my brother (13 at the time) or a friend but never expected it would ever happen.
I was an average 16 year old guy, not too built, but not overweight. My brother, 13, was the same for his age. we have seen each other naked before but I tried not too look too much or I would get a boner easily (I'm not gay but curious and hormonal). I've only seen his dick a few times, but from what I have seen I could tell he is well developed and ahead for his age.
So one day we were both changing in our room (we share a room) before going to go swimming in our backyard. I was somewhat turned away so he wouldn't notice my boner that I just got randomly, but I glanced over and noticed that he had a full on boner as well. I was being daring and asked him if it happens often. He said it does now but he usually waits until it goes away.
I was shocked that (as it seems) he doesn't know how to jack off. I asked him if he does jack off and he asked what that is. At this point I was facing him so he could see my raging boner and I told him to do what I do. I started slowly rubbing my 4.5 inch uncut dick enough that I wouldn't cum too soon. He looked confused and I said that it is a normal thing to do and it feels great. He started to jack off but I asked him if I could help him and he said yes quickly.
I was very excited that I had the chance to jack my little brother off. I reached in front of me and grabbed his dick. Now his dick is actually bigger than mine, his was about 6 inches hard and uncut, and is also quite thick. I was very horny as his dick is huge and my hand is on it. He also has quite large and loose hanging balls with a fair amount of pubes on his sac and around his dick.
I started rubbing it up and down slowly and he was very happy and excited as well. He said it felt great but I told him to wait for the best part. I started going faster and faster when I heard him tarting to breath heavily and moan a little. His face showed that he was enjoying it a lot. I kept stroking him until I felt dick pulse and he shot about 4 ropes of cum onto me and hands. It felt great to be in control of someone else. He said it felt amazing.
At this point I was still super hard and very horny and could cum soon so I told him to jack me off. He started slow but got very fast and I started to cum within one minute. I shot about eight ropes all over the both of us and it felt incredible to have someone else jack you off.
We had many more jack off sessions like this for many years to come. Great bonding moments!