Fucking my Girlfriend's Grandmother

I was dating my then girlfriend and sleeping with her and we would later marry. But she and her parents went away to visit her father's parents. Her mother's mother lived in the same town as them and had been widowed 4 years earlier. Her grandmother was living alone and not mixing in the community like before she was widowed. As I had met her grandmother many times my girlfriend asked me to visit her and check on her while they were away. Which I did and was welcomed by the grandmother and invited in for a talk. I enjoyed the talk and so returned the next day and same thing happened, my girlfriend rang saying they would be delayed returning as her other grandmother had a turn, as she called it and was in hospital. So, I went back to visit her grandmother again, this time she was unsettled and was distracted somewhat. I enquired and was told she had a very annoying itch. I thought it was on her back as she wasn't tiring to scratch it, but it wasn't it was in her vagina, and she had cream from her doctor. But hadn't gotten it in far enough to stop the itching. I was a bit shock once I knew where it was, and I got more shocked when her grandmother asked me to apply the cream. The applicator was only about 3 inches long and didn't reach the affected area according to girlfriend's grandmother. I asked did she have something longer and she said like what, I said a dildo or something similar. I thought all women had those, my mother does. Anyway, she didn't, and she was so desperate to get rid of the annoying itch. She told me to use my cock and push the cream inside her that way. I was shocked but horny and soon had a hard-on and so I fucked my girlfriend's grandmother. She didn't tell me to get off after I had spread the cream inside her and let me finish fucking her. For the next couple of days, I would visit her and fuck her. The day before my girlfriend returned, I turned up at her grandmother home. Ready to apply the cream and she told me the itch was gone and she had no more cream. I was a little disappointed, but her grandmother decided to sex with me for fun as she said she had been missing sex since before her husband passed away. So, I fucked twice and over the next 2 years would visit her on my own and give her a fuck. My girlfriend became my wife and her grandmother stopped having sex with me after tour marriage. She passed away 3 years later, and I remember fondly our sexual relationship now some forty years later.