Happened at age 41. Sorry it's so long, it's just a great memory.
I had been widowed at an early age, losing my wife Kelly to breast cancer. My wife's sister Christine, two years older, had always been very kind to me. She is a very conservative woman (religiously speaking) but has always been very attractive to me, even as a married mother of four.
About 18 months after my wife's passing, I was staying with Christine's family for a few days. Her husband works long hours, and we found ourselves alone having a good conversation pretty late into the night. We had been reminiscing about Kelly, with some laughter and some tears. Christine asked if I had been dating anyone, as she didn't like the thought of me being lonely. She added that she thought I was an attractive man and should have no problem attracting women. I said no, that I just didn't feel right about it. It was very difficult for me, and I sensed she appreciated the honesty. I confided in her that I had been feeling very frustrated and conflicted about this the last few months, and she said she understood. She asked if I had been able to 'take care of my needs', as she knew I had to have urges. I told her that it had been very difficult for me to do this, because I could not masturbate to Kelly without becoming emotionally overwhelmed, and felt guilty pleasuring myself to unknown women. Quite honestly, I was surprised at her question, given her conservative nature.
I confessed my appreciation for her listening, and told her that Paul, her husband was very lucky have such a sensitive and beautiful wife. She was a little embarrassed by my comment, and I asked her why. Like many women, she suffers from a poor self image, and thought I was being I was being too generous. I told her I had always considered her very attractive, and in the past had pleasured myself thinking of her. I was being forwardly honest, not sure sure of her reaction. She blushed, but smiled sweetly. I felt very vulnerable and very attracted to her. Her pretty green eyes sparkled in the dim light. She told me to follow her into their bedroom.
She wanted to know if there was any way to help me, and her voice was genuine. Just the thought of her delicate hands on me caused me to thicken. It was one of those moments that catch you totally by surprise. I said that I did not want to risk her fidelity or marriage, and she agreed. I asked her if she would allow me to see her naked. Again she agreed, but with no touching.
She went and locked the door, and began to undress for me. Knowing she had only done this for one other man, and that she was willing to do it for me was an amazing turn on. She removed her clothes slowly, somewhat sheepishly. I took in her soft curves. Despite her children, she still had very nice breasts. I was surprised to see her pussy lips were shaved, and a nice trimmed mound above. I rubbed my hard on through my pants, and couldn't help but moan a little. As she turned for me, her nice round ass jiggled a little, and it awakened feelings I hadn't felt in a long time.
I told her that I needed to go back to my room now, but my arousal had made her feel beautiful and desired, and asked me not to leave. I told her that I needed a release, and she agreed. I dropped my pants and boxers to the floor, and my erection pulsed. She just stared. I don't have a big cock (about 6', but it is 6' around). She commented on how thick it looked. Just having her stare at me while I stroked it made me want to burst. She sat across from me on the bed. I asked her to spead her legs for me. She did. Even in the pale light of the bedroom, I could tell her pussy was covered in wetness. I invited her to pleasure herself, but she refused. She couldn't keep her eyes from my rock-hard cock. I stroked faster, and felt a huge pressure building. I asked if she would help me finish, and she slid closer to me and tenderly grabbed my shaft. Her soft hand was so small, it hardly encircled my shaft and made it look huge. She stroked it firmly, and I could hear hear breathing very heavily. Her nipples were hard, and she was moaning softly. Looking at her small hand jacking me was all I could take, and I asked her if I could come for her. She looked up at me and all she said was 'Please'. I erupted. I came with such force it actually hurt. Huge streams of cum spewed from inside me, and it startled her, but she didn't stop. I groaned and cried 'Chris!' as I thrust my hips wildly, in total ecstasy.
As the sensation subsided, she slowed her stroke then massaged my tight balls. I opened my eyes, and saw my ejeculate all over her and me. She was trembling. I don't know if she orgasmed from this, but as she got up to get a towel, I saw two large wet spots on the bed.
We cleaned up, and she said I should get some sleep. She gave me a gentle kiss on the cheek, and I went to bed. Months later she later told me that night she masturbated, and for the first time to another man's image-mine.
I always appreciated what she did for me that night, and we have had a great (sex-free) relationship in the years since.