This happened 25+ yrs ago but every time I see sis it still brings back this memory.
At the time I was 15 and like most 15 yr old males the female body was always foremost on my mind. At this point other than a few make out sessions with girl from my school I'd never seen or touched a woman to any degree so as most of you guys will admit seeing a boob or a pussy in real life was always a goal,and as most will confess it didn't matter who's it was....mom, sister, aunt or girl from school it didn't matter, a glimpse of anything was always enough to send me to my bedroom or bathroom for relief. Having a sister that was 15 months older than me and pretty attractive she was often the victim of me trying to see more than I should.
This particular day started out like most, hot summer day, and like most others my parents both worked days and I also had a summer job at a landscaping company and had to leave the house by 8 am leaving sis home alone most days with her friends and our back yard pool which always pissed me off.
It was probably about one in the afternoon when my boss informed me that the piece of equipment I usually ran was broke and he didn't have much for me to do and could go home if I wanted, I naturally didn't argue with that and headed home.
I got back to the house within five minutes and entered through the front door and walked back to the kitchen area looking for food but as I looked out of the patio door overlooking the pool I saw sis in a bikini swimming alone. Well naturally I have to stop & watch for a few minutes always hoping for maybe just maybe a boob would pop out or something..and thinking..she don't know I'm home..maybe she sunbathes topless..or swims nude..god give me something..anything.
After a few minutes she comes to the front end of the pool nearest to me and hangs onto the edge with her arms leaving me nothing to see but the shoulders up and her arms. At this point a little disappointed I was about to walk back to the fridge when I happened to notice one of her arms disappear from the edge and into the water, so again I back out of view and watch for another minute. Then I notice small ripples in the water coming from where she's standing and that catches my attention..and it continues..then I notice her facial expressions begin to change..my mind begins to race...Is she?..sis ?..no way...This girl is the perfect angel in everyone's eyes,there's no way she'd masturbate..no way.
By now the movement caught the attention of my cock as well and it springs to attention in my shorts.
Then the ripples in the water get bigger..I think about at this point the expressions on her face finally left little doubt that I was watching my big sister do herself right in front of me without her knowing!
Well this is more than I can take and certainly more than my cock can take so my shorts hit my ankles and with a firm grip I begin stroking watching her eyes closing and now biting her lip and at times both arms going below the water.
Then she slid one hand up under her top but still out of view from the pool wall I could only see enough to tell that her hand was squeezing her breast.
About now I feel a serious load coming on and try to hold off as long as I can as I watch her shoulders and entire body getting into the movement. Then the moaning begins, even over her radio I can hear her gasping and moaning and now moving ferociously and that was all I could take,
Within a few more strokes I explode everywhere but not wanting to take my eyes off watching my sisters orgasm I let it fly on the carpet and anywhere else its deciding to go.
When calm waters finally came back I looked down and I indeed made a mess and quickly and quietly took my underwear and wiped down the area as she layed her head on her arms and stood there in the water motionless catching her breath with her bikini top bunched up above her boobs.
I slide back into my shorts throwing my underwear in the wash then waited 5 minutes and then made noises as if I just came home and came out to where she was now sitting in a lounge chair in her wet bikini but when I appear she looks up and first thing out of her mouth was..how long have you been home ?..Being the good brother I said I just walked in but I wanted to say soooo bad that had been home for 20 minutes just to see her reaction..lol