I'm 40 and have been married 16 years. My wife volunteers in a "big sister" type program. Her "sister" for the last few years is a quiet, chubby girl who was almost 17 when we met her. She would stay with us on weekends sometimes after she turned 18, and was really like a daughter to me. We were going to take her out on her 19th birthday, and she was staying the weekend. About an hour before she said she was tired and wanted to nap, and us to go without her. The plan was dinner and a couple drinks and then home to see if she was rested and wanted to go to a movie, shopping, whatever. When we got home, she wasn't sleeping, she was drinking. Not wasted, but tipsy. So were we, and actually thought it was kinda funny. I have her a hard time and she tried to shoosh me by putting her hand over my mouth. Then it hit me, her fingers smelled like pussy. I took a second sniff and she looked at me. Her eyes changed, and she knew that I knew. I blew it off and we all went out. I drove, they shopped, we went home. They wanted to watch a movie and my wife had a few drinks. About halfway through, my wife nodded off a bit and anounced that she was going to bed. Just me and my 19 year old friend left. She got real cozy quick and started looking into my eyes. "I love you" she said. And she kissed me. I kissed back and it was on. Her panties were off before I could catch my breath and my finger was inside of her instantly. My god she was wet and tight! She layed back on the floor and opened her legs and I climbed on top. Her pussy was magical. I fucked her 3 times that night before bed. I woke up to the smell of breakfast. When I walked out my wife was in the kitchen cooking. She told me to go get the birthday girl up. After breakfast we drive her home. She hugged us both goodbye and said "next weekend?" And winked at me. Yep, the weekend is here and I'm ready...