My dad and I are great friends, and he knows I've jerked off ever since I was 10. Whenever my mom isn't home, we jerk off together. We usually do this during weekend mornings, when my mom goes to work out. We both get naked, go to the pool, and jerk off under the sun.
One morning, we decided to jerk off on the terrace, which is on the third floor of our house. It was just outside my parents' room, facing the pool area. After a long while, we were both ready to cum. I then said I was going to cum over the terrace, towards the pool. My dad said he was gonna do that too and that he could shoot further than I could. I told him, 'You're on!'
We then got up, jerked off furiously, and we both came at the same time. He ended up shooting further, but I wasn't too far behind. We had to go down and clean it all up, and we ended up jerking off again, completely nude, out in the sun.
We keep this competition going every other week or so.