It all started one day when i was masturbating in my room and my sister walked in and saw me stroking my cock. She instantly backed out of my room, and all I could think of as I laid there stroking my cock was my little sister seeing my erect penis. I had always thought she had a great body and a cute face, she would sometimes walk around in a thong and shirt never thinking anything of it. I started fantasizing about her more and more and finally thought I needed to take action.
My sister has a shower in her bedroom and I would frequently use it whenever we were younger. As we grew older and she started wanting more privacy it would irritate her more and more everytime she came in and i was in there. She started getting into a ruetein of coming in to the bathroom, reaching into the shower and turning it off to kick me out. Once i realized that she was doing this one night I was in her shower and i had a rock hard cock. I heard her enter the room and she tells me to get out of her shower so I put my cock in front of the knob to turn it on and off. Just like planned she came into the bathroom and reached in to turn the shower off. But this time she got something unexpected, when she reacherd in she per her hand directly and firmly on my cock.