My wife and her sister and boyfriend continued to have more pool parties that summer. These pool parties would last until early morning sometimes and occasionally my sister in law and I would go for a drinks and food run. Almost always, my sister in law would ask to pull over and we would proceed to make out that resulted in my taking off her bathing suit top and rubbing and kissing her nipples until she came. Then she would proceed to stroke off my cock very slowly.
One night I had taken all of her bathing suit off and drove around while she masturbated for me. After she came, she said that it was only fair that I not have anything on as well, so I took off my shorts and shirt and we drove around with both of us naked.
My cock was ready to explode and my sister in law must have sensed that because she got down of the floor of the car and took my cock into her warm mouth and gave me one of the best blowjobs I have ever had.
From that night on, her and I had a mutual masturbation session at least once a week. We never had intercourse, only masturbation or oral sex. I was always horny then, either sex with my wife or sex with my sister in law, it just didn't get any better. Or does it? Did I mention that my wife had an older sister?