When I was in junior high, our family moved to a new city. Our house wasn't ready when we got there so Mom and Dad rented a tiny three bedroom apartment for a couple of months in the neighborhood that our new house was in. Mom and Dad were in one room, my sister Mandy in the other, and my big brother Tommy and I shared the third. It was summer, and we all slept late and splashed around in the pool all day while Mom and Dad were at work.
One morning I woke up and saw that Tom's bed was empty, so I guessed he was out at the pool. I was laying there in my boxers under the one thin sheet that passed for the covers on hot summer nights. I started thinking about a couple of really hot girls that I'd seen at the pool the day before. Before I knew it, I was hard, and I reached under the sheet to ease my cock out of the tight boxers and play with myself a little bit.
I hadn't started jerking off yet. One of my friends told me the week before about how he did it. I knew I had to try it, and I was wondering if I was going to dare to try it that morning.
I was stroking myself gently when my brother walked in the room. It was pretty obvious through the thin sheet that I was not only hard, but that I'd been stroking it. He laughed and said something like 'Awesome! You're really going to make the girls squeal with that!'
I rolled over fast to hide my erection and blushed beet red. He apologized and said he'd get out right away and let me finish. I protested that I wasn't doing anything anyway, that I didn't do stuff like that, that I didn't even know how.
He looked at me a second and asked if I REALLY didn't know how. I told him I wasn't that kind of boy. (Yeah, I really talked like that) He said that I was about time I started then.
He said 'you probably don't have any good porn, either-you're kinda young for that.' He asked what I'd been thinking about to make me so hard. I grinned and reminded him about the two girls we'd seen at the pool the day before. He looked out the window and said 'well shit, they're not out there. Let me show you what I use sometimes.'
He booted up his laptop and showed me his porn file and said that as long as I didn't get caught by Mom (he said Dad knew about it and was cool with it) I could use it whenever I wanted. By this time I was standing behind him at the little desk we shared, looking over his shoulder. I was still in my boxers, and he was wrapped in a towel... he'd been taking a shower when I woke up.
He showed me a bunch of great pictures of teen girls skinny dipping in their back yard pool and my hardon started to poke out through the front of my boxers. He saw me tuck it back in, and ordered me to take off the boxers. I hesitated and he said 'don't worry it's cool... we'll both do it... I'm way horny too.' He stood up and dropped his towel, revealing his massive cock, and grabbed some lotion from the shelf above the desk.
He told me to grab another towel, and he put his computer down on the floor between the beds. He showed me how to fold my towel and put it on the floor, then lay down with my hardon on the towel (protecting the carpet) with my head in an ideal viewing position for the laptop's screen. He did the same right next to me. He squirted a big line of lotion on the towel and told me to nestle my dick in it. It was cold and turned me on more.
We then proceeded to watch a slide show of excellent young ladies skinny dipping, while he showed me how to reach under and cup and fondle my balls while stroking my meat with the other hand. He taught me to slow down when I was getting close (to make it last) and how to get frantic with it at the end to make it real good.
We came at about the same time. I still remember the picture that was on the screen when I exploded... a skinny blond standing in the water, facing away, with her sweet ass and pussy just barely clearing the surface of the pool.
We never did it together again, but we talked technique a lot... it's cool to have a big brother.