Helping Neighbor

A nearby neighbor had about 60 bags of dirt delivered to her house. She was going to do some yard work in her backyard but the company that delivered them refused to put them in her backyard. Given she was about 55 years old and not all that strong I decided to help her move them to her backyard. These bags weighed about 50 pounds each and it was a work out moving them. After I was done she invited me in for something cold to drink. My back was feeling a little stiff and tight and so were my legs with all the lifting and squatting. When I mentioned it to her she said she would give me a back rub. I declined but she insisted and off came my shirt. She had me lie down on her couch and began massaging my back. When she was getting to my lower back she mentioned she would need to pull my jeans down a few inches to get to that area. I was reluctant but I was convinced to unbutton and unzip my jeans so she could pull them, and my underwear, down the few inches she needed. Only a few inches of my ass was exposed to her so it wasn't a big deal. She continued massaging my back and mentioned she had to pull everything down a little further. I would say she had more than half of my ass fully exposed to her. She then brought up my complaint about my legs being tight and said she was just going to take my jeans right off now as they would need to come off later to get to my legs anyways. I was now in just my underwear with most of my ass exposed to her as she massaged my back. She finished doing my back and told me she was going to start on my legs now. I expected her to pull my underwear up to cover my ass but instead she pulled them down and removed them completely. I was now naked and made the comment that I didn't know how my wife would feel about this. She told me to relax and it was only a massage and she didn't need to know about any of this. I guess I may have been over worrying as nothing sexual had happened and all that was exposed to her was my ass.
She was doing a wonderful job massaging me and it was feeling really good. I did feel her hand brush up against my balls numerous times when she was massaging legs. It went on for a while when she tells me to roll over onto my back. I did as she asked and now had my front, cock and all, fully exposed to her and was surprised by what I saw. She was naked. She made mention that my back and legs weren't the only things that were stiff and jumped on top of me and began fucking me. I wasn't expecting this and was feeling too good to stop it. After it was all done she told me she couldn't let me get away without giving me a happy ending. She asked me how my wife would feel about this and smiled. She then told me she wouldn't find out unless I told her and if I was ever interested to come back again.