Shelley is an older woman with whom I had been having an off-again, on-again affair for about twenty years. She was a divorced mother of two, a chef by occupation and enjoyed just a little bit of kinky sex here and there. Whilst not particularly good looking, she was at least interesting in and out of bed. I learned early on that she was not really very good at kissing because her tongue was actually quite flat and large and she had a tendency to thrust it deep into my mouth. She never improved her technique over the years but I didn't mind because her hidden talent was giving the best blow-jobs I have ever experienced . During our various flings with each other we played out some pretty wild fantasies and she was always obliging and keen to please. And those head jobs! In between the sex adventures, we talked about various problems and issues. We often discussed our respective families and frequently laughed along the way at their sometimes oddball behaviour. As her children grew from teenagers into their twenties, I felt I came to know a lot about them although I was very strict about not meeting them since our 'friends with benefits' arrangement was supposed to be a closely kept secret. One day Shelley confided in me that her son Cory had recently announced he was gay. Not particularly bothered by that, she reflected on the grandchildren she might never have. Time passed and on one occasion I was visiting Shelley at her house, when Cory called in unexpectedly. He was in his mid-twenties, slimly built with a fresh complexion and wavy blonde hair. I greeted him but any pretence about me being just a 'good friend of his mother' was very soon removed when he said he had known for years she had been seeing me. We talked for some time before his mother returned to the room. Shelley seemed very pleased that Cory and I appeared to be getting on quite well together. He eventually said his goodbyes and left. Shelley immediately reverted from caring mother to sex fiend and went down on me as soon as Cory had gone . As her head bobbed up and down, slurping on my raging cock, I was drawn to how much Cory resembled Shelley in appearance. I soon found myself dreaming that it was Cory sliding up and down my dick and in short order, I pumped out a huge load into Shelley's mouth. She sat back and gasped, commenting on the amount of cum I had shot into her throat. I smiled and continued on but now my focus was clearly on son, not mother. I then asked if I could fuck her arse to which she obligingly agreed, completely unaware that it was her son I pictured under me. Over the next few weeks I connived a way to 'accidentally' bump into Cory and see if I could enjoy his body. Just the idea of having him gave me many nights of wank material. Of course, if Shelley even suspected for a moment of my intentions , I was certain our pleasant arrangement would be quickly brought to an end.