My sister ran a 5k race trying to impress some guy. She was so exhausted when she came home I had to help her into the house and half carry her to her bed. When I put her in bed, she asked me to take off her tight sweaty clothes so she could rest. When I undressed her she looked so hot naked I figured I would try and put my cock in her. I did and she did not react so I kept fucking her until I blew a load deep inside of her. I don't think she even knows what happened