Watching through the hole

When I was growing up I was a typical horny teenager. My sister's bedroom was next to mine. Our closets had a common wall separating them. (it was a thin sheet of plywood) there was a small hole in the wall in which I could see her bed. The morning was her favorite time to masturbate. I could hear the bed creaking and knew that was my clue. I would get down on my hands and knees ( the hole was low on the wall ) and watch in awe as she would lay on her stomach humping her hand. My cock was hard as a rock but was hard to touch as I was supporting myself on my hands a knees. So many times I was humping the air faster and faster. Though some times I would grap a pillow and put it between my legs and hump that. She would go at it for 15 to 20 minutes. Seeing her butt rocking side to side and humping up and down slow at first then picking up the pace was amazing. She usually started out under the covers, but would kick them off as she went at it. I would try to match speed her speed. A few times I actually started cumming without even touching myself, but the feeling was so intense I had to finish off by stroking. They were some of the most incredible orgasms I ever had. There were times I could swear she had 8 to 10 orgasms. At least judging from the straighting of the legs and jerking convulsions. The thought still gets me going to this day.