Best Birthday Ever

I turned 20 and got a brand-new pickup truck off my parents and shirts and shoes off my two siblings. My father's parents gave me a $500 gift card; my mother's mother widow 62 was away but sent me a text saying shed a very special gift for on her return. Anyway, it was a great birthday and the following Friday my grandmother returned late in the evening; I was to visit her Saturday morning she had the whole day planned for me. So, I'd no plans made for the day, my gran is smoking hot as they say for age and she does some modelling. Albeit she doesn't need the money the whole family is very well off. So, giving her time to get over her trip I went to her apartment just after 9am. She met me at the door in her night gown, I at first thought I'd awoken her. No, she said I've been waiting for you, somewhat surprised by her still being in her nightgown. But she was straight to the point, I'd a less than stellar dating record and my grandmother decided I needed more confidents. That was her birthday present for me, a whole day and night of her teaching to fuck a woman, her. She was totally naked under her nightgown, as the oldest child in my family and only male. She thought it her duty to teach me, after an awkward start, I got better each time. Late in the afternoon I thought I should and tell my parents I wouldn't home till Sunday. My grandmother said no need as she had arranged everything with my mother, adding just didn't mention sexual training. I finally got home Sunday afternoon well and truly drained. My grandmother had really trained me well; it wasn't the last time I fucked her as she gave regular refreshers you could say. My dating did improve slightly, but I wasn't a virgin anymore. My father is 11 years older than my mother and had started playing golf instead of fucking her. Knowing that her mother had trained me as they had discussed it before my birthday. She decided she see our well I'd learnt, unable get pregnant again having her tubes tied after youngest sister was born. She planned to visit our lake house on the upcoming weekend; I was asked to join her to clean up the yard. As I didn't have a girlfriend, I'd no reason not to go. Her stated reason was to some painting and recharge her batteries, real reason, fuck her son. I was left in no doubt on the way there why I was joining her, and I was quite happy to please my mother sexually. On arrival, we got a surprise her mother was already there, she hadn't been told of her daughter's plan. But had worked it out and had decided to make it extra special for all of us. We'd a great long weekend and I became my mother's husband's replacement cock. Always willing and I finally got a girlfriend 18 several months later, made a big mistake and we'd to marry. My grandmother and mother never required me to use protection and with my virgin girlfriend I failed to use any myself, result a pregnant girlfriend. Daughter of my father's business partner, no problems we married. My mother and grandmother took keen interest in my wife. Both seducing her together, my wife's mother is deceased, and she was raised by her father who didn't interact with her all that much. Leaving her timid and shy. Only the fact we'd known each other all her life allowed me to date her at first. With my wife seduced by both my mother and grandmother, threesomes and foursomes became somewhat normal for us. One of them or both regularly staying over at night with us. Her being pregnant with her first child was used as the reason, after our daughter's birth, her being a new mother was used. Nevertheless, I'm happy whatever reason they use and really enjoy sex with all three.