We recently had a few inches of snow fall, so school was closed for a couple of days. One of the days I woke up and went downstairs, and when I got to the living room my younger brother was already on the couch, but he was also masturbating and completely naked. I walked over and asked what he was doing, and he asked back 'what does it look like?' 'I know what it looks like, but why are you doing it in here?' 'I dunno, you've never jacked off in here?' 'Yeah, but' He cut me off and said 'well there you go.' 'Yeah, but not when anyone else is here, you're doing it right in front of me.' 'So? We both do it so why hide it?'
He was right, but he was also more of a 'free spirit' than I was. When he was little it was hard to keep clothes on him, and even now sometimes I would walk into his room while he was doing homework or playing games and he would be laying on his bed completely naked.
When I was still standing there, he told me I could go ahead and do it too, if I wanted. We had heard each other countless times and had walked in on each other before, but we had never done it together. I thought about it for a second and already had a tent, so I figured what the hell. I pulled off my shirt and took off my pajama pants and sat down with him, wearing nothing but my moccasins. By this time I was extremely horny, and my penis was throbbing and felt red hot. I glanced over and mine looked a little bigger than his (I'm just under 6 inches, he looked about 5.5), but his balls hung way lower and bounced around with every stroke. Not only that, but while he stroked he would tug on them and roll them around.
For the next 10 minutes or so the room was silent except for the sound of our heavy breathing and skin slapping. He kept squirming around while this was going on, but then he grunted a couple of times and lifted his feet in the air and blew his load all over his chest. He went limp and just sat there, and a couple of times his penis twitched and another blob of cum would squeeze out and run down his shaft. The sight was incredible, and I felt my balls tighten and I was about to cum. Usually I hate getting it on me, but this time I just let it fly, hitting me in the neck and almost getting on the couch. We sat there for a couple minutes talking and joking about the mess we made, but then needed to clean up so we went to the kitchen and grabbed some paper towels.
After that we both decided to stay naked for the rest of the day, and I admit it was incredibly freeing walking around like that and not caring, especially in front of someone else. A few times I would be walking around or standing in front of him and I would start stroking, not to cum, but just to keep it hard and wagging back and forth. This went on until our parents came home, and I threw on my shirt and some lounge pants, ignoring socks and underwear so I could keep that 'free' feeling the rest of the night.
We haven't had a chance to do it again yet, but we talked about it and the next time we have the house to ourselves, we're planning on it being another naked day.