When I was 18 I dated this girl who was a s** addict. She loved to f*** anytime, anyplace, and really anybody. We literally f***** 2 or 3 times a day at least. I caught her f****** other guys several times but couldn't break up with her because I knew I would never find another woman who loved to f*** as much as she did. We had many sexcapades on our own and with other people, but one of the best times we had was when we met her sister for the first time. Her sister had been a secret to the family until she tracked down her father and let the cat out of the bag. My girlfriend was excited to know she had a sister and begged me to fly across country to meet her. She didn't have to beg too hard because I was up for a vacation. We made the trip out to California and met her for the first time in person. She was a smoking hot blonde with a personality like my girlfriend. The first night there we drank until the sun came up and talked about everything from s** to work. Nothing happened except for we got really drunk. The next night we started drinking again and things got a bit hotter. Her sister invited one of her male friends with benefits over and the subject of s** became a quick topic. We decided to play strip poker and it didn't take long before all of us were naked and we switched to truth or dare. I dare my girlfriend to suck the other guys d*** so she dared her sister to suck my d***. Her sister dared her friend to finger my girlfriends p**** and then he dared me to finger my girlfriends sister. We were moving very fast so I dare my girlfriend to lay down and let the guy f*** her p****. She did as she was dared and laid back spreading her legs. He crawled between her legs and fingered her p**** a bit. Then he positioned his d*** at her p**** and pushed in until his b**** came to rest on her a***. Her sister and I sat back and watched as he slowly started pumping her p****. They both got really into it and forgot her sister and I were still watching. I finally asked her sister if she wanted to go to her bedroom and she said yes. So we slipped away and had our own fun. I licked her p**** and fingered her until she begged me to f*** her. We f***** for probably 20 minutes with her having several o****** and then I finished shortly after. We laid there in the bed for a few minutes trying to hear if my girlfriend and the other guy were finished. We couldn't tell but got our answers when we hear my girlfriend ask us if we were done. We all had a good laugh as her sister and i returned to the livingroom. My girlfriend and I stayed for a week and we had fun every night. Her and I eventually broke up but what I really miss is all the fun we used to have.