I grew up in a house where sex and masturbation were seen as dirty. At 11 or so my dad gave me a talk about masturbation. He asked me if I ever touched my penis for pleasure; I told him that I didn't (which was at the time true) and he told me to never try. I had no intention of starting and wondered why I would want to do that anyway.
I later learned about masturbation and understood what it was and why men do it. At 16 I decided to ask my older brother (who was 20 at the time) about sex because I never felt like talking with my parent about it. We talked for a while and I got the courage to ask him about his masturbation habits. To my surprise he told me that he masturbated nearly every day and was shocked to find out that I didn't. I explained that I had been told not to and he laughed and told me it was just part of being a guy. He gave a quick explanation and left the room we shared so I could have some time alone.
At this time I started rubbing my penis and it felt so good. It went so fast because I wasn't used to it. It shot all over me and the bed. I cleaned up and thanked my brother for getting me started.