When I was 13, my family was staying in two hotel rooms for a vacation. My mom, dad, and little sister were in one room and my sister and I were in the other room. Our room only had a queen sized bed, and halfway through the night I got a raging boner. I had never been with a girl before so I started fondling my sister and undid her pajama top and bra. She never woke up, even after I put my penis in her mouth. It felt really good, and it was the first time I came. Not in her mouth of course.