This happended when I was 13 and my brother was 15. My parents left my brother to 'babysit' me while they went away for the weekend.
It was after we went to bed that I heard noises, of course with my parents away I heard every noise the house could possibly make. I got up to investigate, the sound was coming from my brother's bedroom, so not thinking I opened his door to see what it was. There he was cock hard as a rock in one of his hands and a magazine with a naked girl on the cover in the other. I just froze.
It took him a few minutes to notice me, but when he did he put down his magazine, but did not stop strokin. I was about to bolt out of there when he told me to stop. He got out of bed and walked over to me, his cock fully hard pointing straight out. He asked me if I jerked off, I stammered yes, not able to take my eyes off his cock.
He reached out and felt my cock under my pj. My cock immedeatly sprang to life. He told me to take off my cloths, so I did. We stood there looking at each other our cocks pointing. I had seen my brother naked before but I had never really looked at his body. I never noticed how muscles had begun to form on his chest, arms and legs. How his cock had grown, and pubic hair had filled out around it. I realized my brother was a really hot looking dude.
He asked me if I wanted to play. Not quite sure what he meant but totally horney I said ok. He told me to get on my knees and hands, so I did. He said he wanted to ride a horse. So he got on top of me. I could feel his hard cock press against my back. He bagan to rub it back and forth, his hard cock, his balls rolling, pressing. Then he went back and I felt his hard cock between my butt crack. He was just rubbing it up and down against my ass, moaning. This began to scare me and I started to cry, so he stopped.
I looked at his face and he looked so disappointed but I just couldn't let him do what I thought he wanted to do. I told him this and he said that was alright but asked me if I would instead lick his cock. I didn't know what to think, pee came out of that thing. But is was so big and clean and my brother really wanted it, so what the hell.
I got on my knees, stuck out my tongue and gave his shaft a lick. The moan that came out of my brothers mouth was sooooo hot, I couldn't believe it. So I licked some more, I could see my brother was in heaven. I got more and more brave, licking his shaft, his head, his balls until finally I stuck it right in my mouth. He exploded almost as soon as I did that, cum flying out of his cock into my mouth and onto my face.
Soon the cum stopped his cock started going soft and that spark in my brothers eye was gone. I knew he was about to kick me out of his room yet my cock was still totally hard. I told him I would tell if he did not do me. So he gave in and told me to lay on his bed. I did, cock pointing proudly in the air. He came over and sat beside me and placed his big warm hands around my cock and began to stroke. His other hand played with my balls. I was in heaven, I begged him to suck me, but he just continued to rub. It was to late anyways, I could feel the urge, there was no stopping. My cum shot straight up into the air and landed in a big splat on my tummy.
I saw my brother was starting to get another boner, from just jerkin me. I was about to offer to help again, but he ordered me out of his room.
After that evening I looked forword to my parents leaving for I knew I would get really close to my brother (and even later some of his friends).