I am a single masturbating mid-aged man. My parents were divorced soon after I was born and I grew up in a female household with my mom and 18 month older sister. Sis and I were very close and that included fooling around in puberty. Actually she was my first jo bud and introduced me to the female anatomy and how to masturbate it. My mother was fiercely angry with my departed father and would never let him visit.
After high school I joined the Navy and by wonderous chance ran into my father. I arrived for duty at a base in southern Maryland and soon discovered that the person in charge of the civilian personnel on the base had my exact name: first, two middle initials and last. It had to be him and at age 18 I finally met him. He had been through two more wives and lived alone on a place on the bay where he kept a boat and spent most of his free time fishing on it.
After I looked him up and we met he invited me home weekends for most of the summer which were spent out on the bay on his boat. The old man (about mid 40s)was very physical and masculine. He was in good shape and most of the time on the boat we were nearly naked and swam naked in the evenings out there. It was quickly obvious that 'like father like son' is not always true. My 18 yo endowment was well exercised and more than just fair, but my father was hung like a donkey and thanks to him, we were both naturally uncut. We would spend the day fishing our brains out and then dock for something to eat and drink near sunset.
Back on the boat after we got comfortable around each other by the second weekend we'd swim naked and then stay that way maybe even all the next day until again we docked in the evening. It didn't take long before that mutual exposure and the beers and mutually inclined impulses led to open arousal and casual self stimulation. The old man's erection was to my young penis fascinated mind simply breath taking. Just judging by the size of the beer bottle in his other hand it had to be 9-10 inches and half that around.
So we'd sit on the deck in conversation masturbating ourselves at first not even talking about what we were doing. But gradually it got more friendly and joint ending in father and son standing thigh to thigh ejaculating ropes of sperm overboard into the water. What a strange feeling it was to see the seed that had created me. Moreover,it turned out I had a half brother who I'll introduce in a story next. All comments pro and con are most welcome.