It was my mother-in-law's birthday, and I was given the job of delivering her presents as my wife was attending a weekís training course some distance away. My mother-in-law is forty-two and has been widowed for five years. She and I have a good relationship as both our senses of humor are similar. For example, one of her favorites is to greet me with a passionate kiss when we visit, much to my wife's annoyance. Although I pretend to be embarrassed, I secretly enjoy the experience and have fantasized on a number of occasions of giving her one. She has, on a number of occasions when we are alone, given my butt a squeeze or brushed past me and touching my manhood, which has the effect of making me excited. Anyway, I called on her at about 10:00 in the morning and was given the usual greeting of a kiss. I handed over the flowers, chocolates, and a personal present I bought her of a set of black satin underwear. She led me into the kitchen. When she had finished putting the flowers into a vase, I decided to take the bull by the horns and give her a special birthday kiss. I mentioned I hadn't given her a kiss yet and put my left arm round her shoulders. I drew her to me, holding her close and kissing her passionately. I slipped my tongue into her mouth, and she responded in a similar way. While I kissed her, I slipped my right hand under her skirt and up her leg until I was caressing her between her legs. She appeared to be shocked at first, but when I continued to rub her gently, she visibly relaxed and began returning the favor. Suddenly, she broke away and asked me if I wanted a coffee, as though nothing happened. I was frustrated and wanted to know why she stopped. She told me that perhaps we should wait until later. I told her that I had fancied her for a long time and her teasing had left me frustrated on occasions. I told her that I had fantasized about her and had used her image to relieve myself. I then put my arm around her and guided her into the bedroom. I sat her on the edge of the bed and proceeded to give her oral sex. Next, I stretched her out on the bed and, after undressing her and myself, prepared to have regular sex with her. She told me no, not that way, as it was too risky and that she always preferred anal sex. I told her that I had never done anal before, and she then showed me how. We had explosive anal sex that was the best Iíd ever felt. After it was over, we just lay on the bed utterly spent, hugging each other. She told me that she had needed that for some time and that there were many times she had hoped I would have taken advantage of her when she teased me. She said that now that I had done her, she wanted me to continue to service her in the future. I gave her my mobile number, and I have continued to satisfy her frequently since. I enjoyed the anal sex and tried it with my wife, who was against it at first, but now she enjoys it better than normal sex.