My family is very open, and we make no big deal about sex, and things like that. It is common to see my parents (or myself) walking naked in the house. I am 16, and an only child. I have been masturbating ever since I was 10.
One day, my dad caught me masturbating. Later on that day, he called me to talk to him. He first said he was very glad I masturbate, and that I should never stop, or feel ashamed. He then asked since when do I masturbate, how often, and how do I masturbate. He then asked if I wanted to see different methods, which would improve my orgasms, and make masturbation even better. I accepted his offer.
He told me to strip, and begin masturbating like I usually do. Once I got hard, he told me to grab my cock differently, and in a variety of methods. Whenever I didn't understand what he was telling me to do, he would do it himself, holding my penis the way he was recommending. It didn't feel that weird, since no one knows me like he does.
After all these pointers, my dad asked if I ever jerked off with a friend, and if I ever had a friend jerk me off. I have, and so I said yes. He was very happy to hear this, and said that when he was my age, he and many friends often masturbated together too.
I have masturbated a few times with my dad, and I don't find it weird at all. Since he is my best friend, it is just like masturbating with any other buddy of mine.