As an 18 year old I seemed to always have a hardon. I was always horny and looking for a way to get off. One morning I had goten up to go to the bathroom to take a leak. Between me and the bathroom was my two older sister's bedroom. They were sound asleep when I walked past. I tried not to make any noise so I wouldn't wake them. While I was peeing I began to think about walking out into their bedroom with my cock hanging out. It didn't take long for me to decide I was going to do it. When I opened the door I easzed out and checked to see if they were awake. Neither of them had moved so I thought I was safe. I took a couple of steps out into the open and stopped to see if they moved. They didn't so I continued on my way. By the middle of the room my cock was hard as steel and standing straight up. I made my way across their room and back into my room. That was when I had the thought to go back in there and play with myself. I was already stroking my cock when I walked back in. Neither of them seemed to be awake so I eased up beside their bed and stood there stroking my cock. As I was standing ther stroking away I got braver and decided to reach down and lower the cover so I could see my oldest sister's tits in her gown. The cold air made her nipples hard and that scared me a little thinking it would wake her up. She didn't move so I went back to playing with myself. Her tits would rise with each breath and my hand would move faster and faster on my cock. When I felt the urge to cum building in my balls I thought I might better ease into the bathroom and finish but I couldn't make myself look away from her tits. I felt my cock swell as the first stream of cum shot out and landed on her cover. I shot several streams of cum all over their bed before I had finished. It was by far the most explosive orgasm I had ever had. I slowed down stroking my cock and started to turn away when my younger sister asked what I was doing. I nearly shit myself and made some excuse about going to the bathroom and walked away. She looked at my boxers and could obviously see the wet spot and then she looked down at her cover and said yeah right. Later that day she confessed that she had woke up just before I came but that she wasn't sure what she was seeing until I moved. She said she was going to tell but after begging her and promising to do whatever she wanted for a month she agreed not to tell. I had to do dishes and clean the bathroom but the best part of my punishment was when she asked me to do it again while she watched. She thought she was getting back at me but the truth is I enjoyed jacking off for her every time. We never had sex but I did get to finger her and play with her tits alot. She even sucked and played with my cock a few times. I do so miss those times.