Unknowing

So I will start by describing myself. I’m 18 years old, not that good looking. I have dark blonde hair, green eyes and a bit of a tummy. Not huge, but it’s there. I’m still fit as I play a lot of sports and to be honest, I masturbate a lot. I have a huge sex drive and it doesn’t seem to matter if I wank everyday or not, I still always seem to want more.
So it all begins with me getting sick. I had been in hospital for about a week. I had gotten a very bad chest infection and after a week of it they sent me to hospital to get stronger treatment. I had been in and finally gone home. I had now been home for another 2 weeks and I was finally feeling like my old self. Needless to say, I hadn’t blown a good load for 4 weeks and I felt like my balls were going to explode inside my sack. They felt so swollen from not having released any sperm for so long.
It was currently 1:00am and I thought after lying on my bed for hours unable to sleep I would go to the bathroom and get a load out, thinking this would help me rest. I got up and headed to the bathroom. When I got there, the door was closed and I could hear the shower just starting. You could always tell when it had just started, the pipes make a soft squeal noise. Who the hell was in the shower at this time. I looked around and spotted my sisters door slightly open. I headed over to peek inside. When I looked in I could see Selena on her bed. It must have been Matt, her boyfriend in the shower. He stays over sometimes after they’ve been out late.
So at this point I should describe Selena. She is very slim, athletic, long beautiful blonde hair, bright blue eyes, a nice set of C34 tits and a very tight flat stomach leading down to her magical crotch area. The front has the perfect v shape and the nice small gap in between her legs. Her butt is just as tight and firm, with a wonderful lift, giving her the perfect bubble look. She was 17 years old.
So while my parents always thought Matt stayed in the spare room, I knew he often stayed in her room until early morning then he would switch. I also couldn’t help but to notice how stunning Selena looked, lying there on her bed with her tiny lacy top and shorts on. She often slept in these. I also knew she would not have panties on under the shorts. Her chest looked wonderful, raising and lowering with her breathing and her tight tummy showing itself to me. My cock got very hard very fast. I could swear I had the biggest boner I had ever had, looking at my younger sister.
I could no longer hold back, as I slowly entered her room. I crept over to her bed and was enjoying looking her up and down. She had her sleeping mask on, which meant she was tired and didn’t want to be disturbed. My mind was going crazy with thoughts of what I could do. Knowing everything in my mind was wrong I tried to tell myself to leave. But with Matt only just having gotten in the shower he will be gone for a few minutes at least. I decided to lie down on her bed next to her, and just gently cuddle her.