The first and only cock that I ever sucked was my own.
When: I was 13.
Where: It was in my bedroom where I usually masturbated. I was wondering if there was a better way to get my pleasure, other than just stroking my cock.
How: I was fairly thin and flexible back then. So, after a few futile attempts, I tried the "legs over the head" position and managed to get about half my cock into my mouth
At first, it was slightly uncomfortable, but after a few successful tries I got good at it. Truthfully, it was one of the most amazing feelings, both emotionally and physically that I have ever experienced in my life.