My sister loves to take baths. She used to spend hours in there. I had always wondered what she did in there. One day I put tape over the door latch so it couldn't lock. After about an hour I walked into the bathroom as if I didn't know she was in there. She was actively masturbating and didn't stop when she notices me. I watched her for about 5 minutes. She finally turned her head towards me and told me to come help her. She rubbed and pinched her nipples and put my hand on her tits.