Waking up Sister

I hesitate to share this as I find it somewhat embarrassing. My parents decided to have my sisters room repainted. So she came to sleep in my room in my double bed. I was only in my early teens so I was not ejaculating yet, but I really enjoyed my dry orgasms when I first discovered them. I've been jerking since whenever I can which was mostly at night. Anyway, I didn't think much of my sister and I sharing a bed and I certainly did not think of her in a sexual way. The first night I jerked off as usual with my sister next to me, stopping when I felt her stir in her sleep and in the morning, my sister kept complaining that she couldn't sleep cos the bed kept shaking. My parents asked me if I had the same experience and I said no but I think they might have guessed what the shaking was. I was still clueless and thought my sister was imagining it. The second night, I was pumping uninhibitedly thinking I wasn't disturbing anyone until my sister woke up and asked me what I was doing that was making the bed shake. I pretended I was asleep but she knew I was faking, and she knew that I knew so I just came clean and told her. Since I always had my bed all to myself, I didn't know people could feel vibrations when I jerked. I was really embarrassed and begged her not to tell our parents. She agreed but wanted to see me jerk so I did. She watched me jerk off two more times that night. On the third night, I felt the bed shake and realized my sister was masturbating and deliberately wanted me to notice. That was the first time I'd seen a girl do it and it got me hard. I didn't want to jerk off that night cos I was embarrassed about getting caught the night before but after seeing that I started stroking. We masturbated together that night and the next few nights. There was no touching each other, just watching each other masturbating. This went on for about a week while my sister's room was painted and aired out. One night, while we were masturbating, I ejaculated. It wasn't a lot so I didn't notice until morning when my pajamas were stained. I was happy that I had started "shooting stuff" as I had read about, but unhappy that I wouldn't be able to jerk off without tissues anymore, plus I used to have several orgasms in succession but I found that my dick grew soft after cumming. My sister moved back into her room shortly after and I had my bed to myself again. I wasn't sad or anything cos I still did not see my sister in a sexual way at all. I sometimes wonder though, if my sister continued masturbating after she moved back to her room and what are her masturbation habits now.