Fascinated With My Big Sister

I want to stress that nothing ever physically happened. When i was 13 I was already a chronic masturbator. My oldest sister is 4 years older than me and had a great body. I never noticed it until one night after she showered, she was wearing just her panties and a long t-shirt. Sitting on the couch she would put her legs up on the couch and pull the tshirt over her legs and pull her arms inside. When she did this it stretched open the arm holes and you could see right through to her tits. They were really big with pointy puffy nipples. I just sat there staring as long as i could. After she got up and left i ran to my room to jerk off. This began my obsession. It eventually led to me hiding a camera in her room while she was in the shower. When i watched the tape i could see her fully nude. I would watch that tape so much and jerk off that the tape started to wear out. In the summer i would be upstairs in my roo. While my two sisters laid out in the backyard to tan and i would jerk off watching them. One time i could hold it any long and i came out the window. I always dreamed they would see and would want to watch. But that never happened.