My wife's Mother

I'm Pat short for Patrick 29 I live and work on the family property, as the youngest of 3 and only one not to go to university. I stayed on the farm and run it alone now my parents retired to live in the local town next to my sister and her family. I can always call on them for help if I need it, but that is a rare event. The property was purchased in the 1930's and has been ours ever since. Growing up here was wonderful, there's a cave on the nearby hill that was enlarged in the late 1800's and in the 1920's was used to make moonshine. Only the first 40 feet was enlarged and squared off like a room and the cave goes into the hill further, but gets narrower the further you go. My friend Julie 25 lives on the outskirts of the town with her mother Grace 42. I asked Julie to marry me and she agreed, then Julie went to the city do a course was gone 5 months. So I was home alone and the first weekend Julie was away her mother Grace came out to visit me. Grace had heard the stories of the cave and other weird and fantastic things that were found in and around the area. Grace is into the occult and witchcraft, she wanted to see the cave for herself and with Julie gone. Grace took the chance as Julie didn't want her weird beliefs getting in the way. I decided to at least show the cave and keep my future mother in law happy. I grabbed a couple of battery lanterns and drove up close to the entrance. The first part of the cave wasn't of much interest to Grace and she wanted to see further inside the cave. There's a another chamber further in and it has some weird marks on the walls. No real history to the marks as tests show they have only been there since the 1920's at the earliest. But the marks was what Grace wanted to see and she didn't believe they weren't ancient. But after a time I was ready to head back and told Grace it was time to leave. But she wanted to do a ritual and thinking it would better to let her said okay. To my great surprise she stripped off and stood before me totally naked. Then she started dancing around and chanting something, I myself was only interested in her nice body and got a hard-on. Grace finished her dance and straight out asked me to fuck then and there. So I did and after we returned to my house both still naked and bathed together and spent the night together. Sex between me and Grace became regular at least once a week. Julie returned and we married the following weekend, both Julie and Grace moved in with me. Julie already knew I had been fucking her mother as Grace had told her. They never kept secrets from each other and Julie had asked Grace to make sure I was satisfied while she was gone. At Grace's request we spent our first night of our marriage in the same chamber as I'd fuck Grace. Grace claimed it would sure our first child was a boy and we also included Grace in the sex that first night as well. That was four years ago and now I've 3 children 2 boys and a girl. Our first was indeed a boy and so was my only child with Grace, also from that night in the cave. Either she forgot her protection or the magic bypassed it. We all have had sex there together since. But our daughter wasn't made there, but I still get to fuck Grace regularly now.