My dad was self-employed in a business run from home. Every day after lunch, he would retire to my parents' bedroom to take a nap. I never really understood why.
One day at about age 10, when I was not in school, I had quietly entered the bedroom area of our house. I knew to be quiet, because dad had gone to take his afternoon nap. At one point, I was located where I could see from my room into my parents' room. My dad was lying on his back stroking the biggest cock I had ever seen. I had never seen any adult erection at that time in my life.
That cock had thick veins all over it, and an elarged, very red head. I was mesmerized, but couldn't look away or leave. In a few moments, dad let out a muffled groan and ejaculated a few spurts of white cum juice into a towel. I didn't even know about semen at the time, although I was jerking off, but not able to ejaculate.
For the next few months, any time that I could be in the house just after noon, I found myself trying to observe that phenomenon. I had some successes and determined that this was a daily event. My mother was always downstairs during these episodes, and I now think she knew all about it.
One day after I had been observing this for months, my dad told me that he knew I was watching him in the afternoon. I was certain that I was going to pay a dear price for my carelessness in being discovered, but instead, he assured me that it was OK. In fact, he asked if I would like to watch close-up.
Naturally, I wanted to do that, so he invited me to their room and pulled out his big soft cock. Saying that he knew that I had been watching him, he asked if I would like to take care of doing it for him. My heart leaped. I took his cock in my hand and it immediately began to grow. I couldn't hardly believe how big and heavy it was.
It grew into full erection and I could feel the throbbing, pulsing of his heart rate. As I began to stroke it, I was able to notice how it was drizzling pre-cum. I rubbed his pre-cum all over the head of his cock and stroked it faster. He had his hands working on his balls and told me to watch for the cum. Streams of hot white cum shot from his cock, some onto my hand, some onto my arm, some into the towel.
After that, we jerked together about once a month. I finally started cumming myself about 2 years later, which made him seem pleased. He also jerked me off a few times after I started cumming, but we mainly jerked ourselves off when we did it together. It was a fun time for me, and it lasted for about 5 years. I wish he were still alive so that we could still do that.
Those lessons made me a confirmed masturbator, as well as a voyeur. I love to watch.