My name is Mike, and my wife, Susan, and I had been married for four years. They had been a terrific four years, full of good times and terrific sex. At 5'5" and 115 pounds, Susan was a perfect partner to my 6'1", 195-pound frame. Her full, c-cup breasts were perfectly proportioned to her gently rounded hips and curvy legs, and her trimmed pussy easily accommodated my nine-inch cock. We were a great couple with lucrative jobs which helped us live comfortably in a large home in an upscale neighborhood. Susan and I had met in college in Pennsylvania and had been together ever since.
Despite our very active and diverse sex life, my one secret obsession was for Susan's younger sister, Kristine. At 22, she was five years Susan's junior, and she exhibited the energy and playful exhuberance you would expect from a college junior. That quality made her very attractive to me. But Kristine was also very different physically from Susan. Kristine was 5'7" and very thin, but in a fit, physical way. An avid runner and swimmer, Kristine had a firm abdomen and toned legs. That only served to highten the feminine quality of her small, yet perky breasts that seemed to make themselves known in whatever Kristine happended to be wearing. Kristine's feathered dirty blonde hair gave her the perfect appearance of a toned, tanned California beach bunny.
In all the years I had known Susan, I secretly harbored my lust for Kristine. I never imagined I would ever act on it, and just assumed it would remain my private fantasy.
Things changed the summer Kristine came to spend a month at our house during her summer break. We lived in the New Jersey suburbs, and our large home and secluded pool made it a great retreat. Originally from Ohio but going to school in Delaware, Kristine didn't want to make the trek all the way home for summer break. So Susan struck a deal with her sister to stay at our place in exchange for some light housekeeping chores.
It was the perfect deal for Kristine: up by nine o'clock, chores done by eleven, and the rest of the day reserved for hanging out by our pool in whatever skimpy bikini she decided to wear. She often went out to clubs at night with some of our neighbors' daughters who Kristine had befriended, but she never stayed out the entire night and often was home by midnight.
On one particular weekday afternoon, Susan had dressed and headed off to her job as a fashion buyer in New York. I had some time off to take, so I was taking days here and there during the summer to do yard work or other projects. On this particular day, I intended to do some light pruning of the shrubs and to fix our sprinkler system. It was a typical New Jersey summer day, with temperatures in the 90s and high humidity. While I'm certainly in good shape, the weather was even getting to me a bit and I much rather would have preferred being inside in the air conditioning.
Around noon time, I made my way to a row of hedges that run along our backyard fence. I started clipping the overgrowth from the bushes, when I noticed that there was music coming from the backyard. I figured Kristine must have cranked up the stereo while she lay by the pool. It was so loud, I'm sure she couldn't even hear my shears clipping the shrubs. Taking a break, I peered over the fence to see what was happening. What I saw truly stopped me cold.
Lying on a lounge chair was my sister-in-law, her bikini top untied and tossed to the ground, with her hand gyrating inside her bikini bottoms. Kristine was lost in a torrid session of masturbation right on my back patio. Her firm, tanned b-cup breasts twisted and bounced, with dark, small nipples fully erect. I should have turned away right then and there, but I was mesmerized as her firm, half-naked body gyrated and jerked with every move of her hand.
After a few minutes, I finally tore myself away. I was doing all I could to prevent the huge hard-on forming in my shorts. I struggled with the feelings I was having; after all, my lust for Kristine was a fantasy, a private affair in my own mind. What I had just seen was too real. I quickly hurried back to the garage before Kristine became aware of my presence. Once in the garage, I composed myself and decided to cool down by checking the outdoor sprinkler system, which had a control box in the basement.
