The first time I masturbated long enough to have an orgasm and ejaculation, I was 13 years old. I used to go to a tutoring center and before one would actually have to meet with their tutor and do homework they would have some time to either play a computer game or go into a reading room and read.
The entire week I had been getting more erections than usual and it was like my hand was drawn to them because they would be bigger and harder each time. I would usually start touching it and feel something stirring and I'd stop because I didn't want to deal with seeing the 'gross white stuff' that I had heard comes out.
So, I had been controlling myself as well as one could when they are 13. At the tutoring center I was in the reading room with, as I remember it maybe 10 other kids all engrossed in their various books and magazines. I was wearing sweat pants and I had one hand under the table rubbing my penis, I don't think I was obvious I certainly wasn't trying to be. I wasn't exposing myself, I wasn't leaned back in my chair, the only clue might have been that whatever magazine I was looking at I had been staring at the same page for way to long. It was obvious I didn't care what was on that page, I was looking past it.
I was wearing sweats and no underwear so although I never exposed myself I had good access to my dick from the outside of my clothes. I never put my hand in my pants I just kept rubbing on the outside until I felt my stomach start to stir but this time unlike the other times I continued.
Then I let out an 'ugh' that was louder than I expected, and everyone looked at me some giving me sharp looks because the reading room was generally a very quiet place. It felt like I was pumping cum forever and I had a good sized spot on the outside of my sweat pants. When I looked up this older teenager (16-18 years old) was smiling at me, I'm pretty sure he saw because he would always try to start conversations with me from that point on.
So after I ejaculated and I saw this guy smiling at me I got up to see what had happened in the restroom and as I was leaving my tutor was calling my name but I rushed into the restroom anyway. I looked at my dick and it seemed like it had grown and on the tip there was left over semen, in my pants and on my legs there was semen. When I tried to clean the spot I ended up with a big wet spot on my pants which when it dried later the semen stain was still visible.
Anyway, I came out of the restroom and that older teenager was waiting for me. I don't remember what he said but I didn't engage him, I was already embarrassed and feeling self conscious.
That was the story of my first ejaculation, I hope that you enjoyed it. I'd love to hear other first time stories, thanks.