I simply watched the hidden fingers working back and forth at a snail's pace IN that forbidden spot between her legs.Then it dawned on me from what my...girl pal Barb had told me about her own "busy fingers"... Suzanne was masturbating! OH COOL, the girl was catching some rays and a BIG "O" to go along with the suntan! THIS I GOTTA SEE!!!The near naked girl was far from pretty yet had her own mysterious attraction to offer. What about her distended midsection? I had seen plenty of generous. .. I'm... I'm gonna cum... Oh God" I grunted."Do it, cum in your little sister, fill me with your cum, big brother." she moaned in my ear. I lost it right there. I thrust all they way up into her and my balls slapped her ass roughly, and I grunted, sending spurt after spurt of my incestuous seed into her pussy.I continued small strokes during my orgasm, and just set there for a few minutes. When I finally rolled off her, I came out with a small plop. We lay next to each other on the floor. It too was never crowded. Peter and I were normally the only ones using the facility. We developed a routine early in our stay. After returning from skiing we'd put on our suits and bath robes and trudge to the spa with our towels tucked under our arms. It felt so good to relax and soak and stretch our sore muscles while we recounted the day together. Pete’s casual touches, even the few times there were other people, made me feel so wonderfully desired. After showering we would lie naked atop. It's what I do. Don't ask me why. I just love being naked in places I shouldn't be, especially outside. When I get the urge in the middle of the night, or after school, or out in the park, I gotta strip down, and if somebody sees my pussy, that's a bonus. That's why I was at the Mini-Mart tonight.The lady at the counter was a chubby little thing in one of those orange and red store smocks, which is all I could see over the counter. She had short gray hair. She barely looked up when I came in. I.