My wife's mother recently came into town for the holidays. Since she was in town for 10 days she stayed with us to save money. One evening she invited a girlfriend of hers over for dinner and drinks. Because she had a few drinks and it had begun to snow we told her friend she should stay. She agreed and we all continued to enjoy ourselves. My wife and her mother shortly fell asleep on the couch so I excused myself for my evening shower before bed. As I exited the shower my mother in laws friend was standing there. I was shocked and did not cover up immediately. She stared at my penis said "you've got to be kidding me. You're gorgeous and hung????????????????" Before I could respond she got on her knees and put me in her mouth. Because of the shock and alcohol I did not immediately pull away. Before I knew it I was completely erect. She stood up and told me I was twice the size of her husband. She began to take off her clothes and for a woman 15 years my elder she was in incredible shape. She went back down on me and I had yet to speak a single word. After a few minutes my cock was as hard as it has ever been. She pulled away and said she had never been so turned on in her life. She said that she thought she could orgasm from just sucking my dick. At this point I could not stop. I pulled her up and sat her on the counter top. She grabbed by penis as I was about to enter her and she asked me to go slow because I have the biggest dick she has ever seen. I entered slowly and I could not believe how hot and tight her pussy was. I began to fuck her with half my penis when she began to moan "deeper". I began thrusting deeper with each push. I was about 3/4 in when she had her first orgasm. She leaned her head back and screamed "Holy Fuck" so loud I thought she woke up my wife and mother. She then begged for every inch. She was so wet from her orgasm that she was able take the last few inches of my dick. She begged me to fuck her brains out so I started thrusting harder and harder. She was having orgasm after orgasm. I was getting close to climax but wanted to fuck her from behind. She has the tight ass that only a fitness instructor would have. I turned her around and she told me she would do anything I wanted. After a few minutes I told I was ready to explode. She quickly turned around and went back down on me. She placed both hands around my cock and started sucking the top of my penis. It only took two pumps of her hands and my dick erupted. She swallowed every drop and stared up at me still holding my now half hard cock. She told me she had never had multiple orgasms before and she had so many tonight that she lost count. I kinda laughed and said "I guess size really does matter". She agreed and told me she would fuck me anywhere anytime. She then put her clothes on and went back downstairs to sleep. I got into bed and quickly passed out. She was gone before I woke up the next morning. I did find her business card in my wallet. Turns out she works at a gym very near my office. I stop by a couple times a week for a quickie. I still fuck my wife almost every night and she's amazed at how long I last on the nights after I have visited her moms friend. Of course I haven't revealed my secret I just say it must have something to do with a good workout. She literally told me to keep doing what I'm doing because our sex has never been better. Obviously I agreed!