Our families knew each other, and they were supportive of us being together. Everyone figured that we would eventually marry, and it was great that our families were so close as well. We often spent holidays and vacations together, and there was never anything weird about Kristin and I being together as a couple.

Kristin's younger sister Lisa had always taken a shine to me, and every one laughed at the way she flirted with me. Being four years younger than Kris, Lisa's affections were seen as merely "puppy love," as she was so young. It was obvious to everyone that she was trying to emulate her sister, and it fell in place with everything else that was going on between Kris and myself.

As we grew older, Lisa's flirtatious ways took on a whole new level. She had developed into a hot little number, and I often found myself fantasizing about the flirtatious way that she always seemed to have when I was around. As Kristin and I grew more sexual, I looked at Lisa in a whole new light.

Lisa's 14th birthday rolled around, and Kristin and I made plans to take her out to celebrate. Lisa had recently broken up with a boyfriend, and she was a little down that she had no one to celebrate with. Her parents were out of town as well, further adding to her misery. Kristin and I took it upon ourselves to make sure she had a great birthday.

The plan was for me to meet Lisa at their house and when Kristin got home from work we would all head out. Their parents were going to be out all night, so we knew we could get away with a little more than if they were around, and Kristin and I had planned on getting Lisa drunk to really celebrate the birthday.....(cont)