My oldest brother (21), myself (16), and my younger brother (11) went on a car trip to Disneyland for my younger brother's birthday. We live in Seattle, so it's quite a long trip. We were in the middle of nowhere at around 11 or 12 at night when the car ran out of gas.
My older brother decided that he was going to walk to a gas station since no one had a cell phone to call AAA. He told us to stay here and watch the car (it was new).
Ten minutes after he left, I got extremely horny. I hadn't masturbated in a few days and needed to blow a load. I was sitting in the front seat with my younger brother in back and I thought he wouldn't notice me if I discreet about it. A few minutes into my session, my brother peered over the headrest and saw my hand pumping my penis.
He asked what I was doing and I said that I was masturbating. I asked if he had done it and he replied with a no. I then preceded to hop in the backseat. I told him I was going to show him how to do it. I took my pants and boxers off and told him to do the same. He was a bit skeptical, but he slid his pants down to his ankles.
I reached over and grabbed his fairly large penis for his age and started pumping. I told him to do the same to my cock. He started stroking mine. He and I started moaning pretty loudly. With the lights on over the freeway and the cars zooming by, I was so excited.
After five minutes, he was screaming, so I sped up and he came all over the back seat. After he was done, he reached his other hand over to me and used both his hands. I had hands free so I put a few fingers in my ass. I loved doing this alone, but with my brother jacking me off, it was even better. He started speeding up with pumping and shoved my fingers farther in my ass and I came soon after.
When my older brother came back with the gas, my younger brother and I were sitting in the backseat with our pants off. He just smiled, loaded the car with fuel, and drove off. He pulled his pants down soon and started masturbating and the two of us in the back started up again as well.