Dirty Desire

This happened when I was grounded for one month for doing something. I was in my room with my door open cleaning my room. I came across my younger sister's Barbie dolls and I thought I would have a little fun. I started playing with them when I pretended they were having sex. Well, that got me really aroused so I started rubbing myself. I lay down and pulled up my shirt to see my D size boobs. I held down my pants with my left and, with my right one, I was circling my clit really fast. Then, before I was going to orgasm, my sister walked by my room. She yelled at me and told me not to do it again. (Even though I know she does it, I was too embarrassed to say anything.) So, I went into my living room and decided to finish what I started. It took my like six seconds to orgasm and the thought of getting caught aroused me. Whenever I masterbate now I think of all the porn I've seen and about that one incident. I've always wanted to masterbate in front of someone or do it for them. So, thinking about what would have happened if my sister didn't yell at me is my little desire.