This story took place when I was almost 15 actually.
Me and my mom live together because my parents are divorced and I am an only child. I had learned how to masturbate when I was around 13 years old.
This story takes place when I was in my ninth grade year and I was 14 and 1/2. I was about 5'6' with black hair, a little underarm hair and a decent amount of pubic hair for my age. Anyway, one day when I had just got home from marching band camp, I was tired and exhausted. I grabbed something to eat and headed up to my room. My mom and I are very close and she has actually seen me nude before but that was when I was about 13. I closed the door behind me and took off my clothes and sat down in my 'special' chair, which is facing the door and started to masturbate. I started to move my hand up and down again and again for about 10 minutes.
Then all of a sudden my mom comes in the door. I had my left hand on my penis and my right hand holding on to the chair behind me. She was going to ask me if I was going to take a shower, and then stopped in the middle of her sentence and said 'Sorry, finish up' and then shut the door and left. I was shocked and surprised. So then I finished up and then went downstairs to watch t.v. trying to avoid my mom, but eventually she came downstairs and gave me a little talk. She said 'I know what you were doing feels good and I am okay with that. I will remember to knock next time.' And that's the last time we talked about it for a month until she caught me doing it again after I was rubbing my penis through my pants. I stood up and had a big cum spot on them. She laughed and it was kind of embarrassing, but that is a different story.