When I was growing up we moved around a lot. But in one house we lived in, my sister's room and my room were right next to each other. The closet between our rooms was divided by a thin piece of plywood which had a small hole in it about knee level. Once I had discovered it - wow, the shows I got.
My sister had a really good figure. About 36C-26-34 and 18 yrs old. I was about 16 and forever horny. I would get up early on Saturdays just to watch the show from my small vantage point. I would see her toss and turn and would usually throw the covers off herself at some point. She slept topless quite often and I couldn't help but start rubbing myself as soon as I saw her pert tits.
After watching and stroking for awhile, she would wake-up and start stroking her breasts and lightly pinching her nipples. By this time I would be really worked up, so I would have to stop and relax for a minute to keep from cumming. Then she would turn over on her stomach and slide her hands beneath herself and start humping. Her hips would buck from time to time and she would as rock them back and forth. Occasionally I could hear a quiet moan or gasp (that wall was pretty thin). She would rock and hump faster and faster, then she would stop. But she would start all over again and again. I assume she was having multiple orgasms.
After about 5 or 10 minutes of watching this and stroking my cock, or sometimes just dry humping the air as I was on my hands and knees, I would shoot my cum all over my hands and the floor from my orgasm that seemed to last 30 or 40 seconds. One time I came so hard I bumped the wall a little too hard and made it creak. My sister looked over toward the wall but I don't think she ever suspected anything or saw the hole ( at least not at that time - I think she may have later ).
Hope y'all enjoyed the story. I've got many more if any one is interested.