After Sophie gave me the best blob job, we showered and had a solid breakfast. I needed the energy, Sophie told me, because I would be learning hard all day—hard being the operative word. After coffee and pancakes, we returned to my bedroom to start my lessons. The first part was the formal search for Sophie's G-spot. Try thinking of it as a clock, with my clit as midday. We agreed that around half past three was the correct time. Having got that out of the way, she grabbed my cock.

Sophie shook it several times until it was at full mast, then let go. As I stood, she got me to describe how it hung slightly to the left and had a slight banana twist at the top. The most off-centre part on the same clock set-up was at ten o'clock. Sophie explained that I needed to try and get my ten o'clock cock to match her three-thirty G-Spot when I was fucking her. Given that it didn't match up, what position would make that happen?

I gave the correct answer, but Sophie was more interested in how I could try to match up in the missionary position. She had me corkscrewing as I drove in and out until I could scrape her G-spot every time. I managed to make her come twice before I told her I was coming soon. I was told to stop, pull out, and focus on oral sex until I could make her come again. By the time this happened, I was only half erect. I could fuck her to another three orgasms before I had to stop again.

For almost all of that Saturday afternoon, I got edged until I was able to hit her G-spot without thinking about it. As a reward, I lay on my back whilst I got another blow job. This one is way more intense than the one this morning. Sophie let my come spurt all over my stomach and chest. She slowly and deliberately licked it all off until I was hard again. Lesson number one, out of the way, we tried different versions of the missionary until we fell asleep around midnight.

Sunday covered off spooning for the fucking and her breasts for the oral sex. I was pretty pleased with the fact that before we broke for lunch, I could make her come just by sucking her nipples. As a reward, that evening, I was shown how to open up her ass with my fingers. Then how to slip my cock slowly in her using lube. Before I fell asleep that night, I was fucking the ass of my stepmother and loving every moment of it.

I was pretty taken with her attention to detail. Whilst I was licking her out using a given method, me having been given the rudimentary outline. She trawled through her extensive collection of porn to find an example to show me that I was doing it right. The clip was from a female-on-female film, but as Sophie pointed out, oral sex for a woman wasn't a selling point in a heterosexual porn clip, less still stepmom porn which we both seemed to watch a lot of.

The other thing I noticed during the weekend was how much time there was during sex for chatting. In the beginning, we tended to make out a bit, but once we hit a position, it was just fuck, fuck, fuck for a while until Sophie came or I got close to spurting. This gave us a lot of silence to fill. I did like hearing the squelch of my cock in and out of her well-lubricated pussy, but you can have too much of a good thing.

Our conversations took up from where they had left off the last time Dad was away. Mostly about Sophie's sexual preferences, but at some point that evening, she told me that she and Dad were swingers. I stopped what I was doing immediately, not because I was in shock but because it wasn't that much of a surprise. Dad and Sophie's lifestyle, including me fucking her right now, indicated they were not a vanilla couple.

I had also done some internet digging on Georgio's since Dad's birthday party, and there were some interesting comments on some sex chatlines. The indication was that although it was a raunchy pick-up joint upstairs, there was a sex club running in the basement. Details were sketchy because nobody was going on the record telling tales. Reading between the lines, it was more than it appeared, but again, that might be wishful thinking.

The bombshell led to an initial confirmation, several follow-up questions, and a longer explanation from Sophie, which made me realise that Dad had been into this lifestyle for far longer than I initially thought. It would seem that it preceded Sophie and also preceded all of the other girlfriends I went on a summer holiday with. There was a pleasant realisation that I had not been the problem to my father's sex life that I thought I had.

I had always figured that his previous girlfriends left him shortly after our summer holidays together because the existence of a teenage son was a problem. It turns out they all left him because the women insisted that he give up his swinging, swapping lifestyle, which he was not prepared to do until Sophie, who liked it perhaps better than my father did himself. The next evening, I asked her how Dad had got involved in the first place.

I could not imagine my mother doing anything like this, and I wondered how far back it went. I also figured that getting involved with a young single man, even one with a big cock, was not easy in the pre-internet age. She started to talk about him getting engaged through some of the couples he originally lodged with whilst I was tiny. She even came up with a joke: lodger with benefits. He kept the wife of the house happy and got invited to join their swapping parties.

This triggered a light in my head, and while working out, my grandparents organised those lodgings; I blurted out, 'Were my grandparents' swingers as well.' Sophie just laughed, and suddenly I realised she had fucked him. When I asked, she did not attempt to hide it; she was proud of the fact she had slept with three generations of her husband's family. And your grandmother is very hot, she added. I'd never thought of this, but she was.

I suddenly remembered that grandma was not my Dad's mother. His birth mother died before he and Grandad moved to the coast. I didn't ask if Dad had slept with my grandma because I was sure he had if Sophie had. Wow. The rest of the evening was a little hazy because I thought about what might happen when I went to Christmas lunch at Grandad's house. A fantasy of Sophie getting three generations of cock in her three holes crossed my mind.

We slipped into a regular schedule for the working week. Generally, it started with the day's highlight: Sophie carrying out a reverse striptease to go to work. We had moved into her bedroom on Sunday night because of work, and I only had to throw on the same clothes each day. After she showered, Sophie would put on a suspender belt and stockings, plus her chain mail white bra. She offered me a choice of slutty knickers for her to wear.

Then she would put on a sheer blouse and one of her skirt suits: kitten heels and a coat to go over the top. I generally followed her for a kiss at the front door. I was under strict instructions to make sure all my coursework was completed before six when she returned. Sophie would pull up her skirt, then lean over the arm of the sofa. I would pull her panties to one side and fuck her for a couple of orgasms. Then, shower, dinner, and the lessons would continue until eleven.

We focussed a lot on oral sex. Sophie had ten different methods of getting off with differing combinations of fingers, tongue, and lips. We went through each combination each evening. Start with me describing what I would do in which order, then carry it out on her genitals. The first three were more about edging and extended play. Four to eight were more to open up her pussy as wide as possible to get my cock inside her. Nine and ten were all about speed to orgasm.

By Thursday evening, Sophie told me I had done well enough to get full marks. We spent the rest of that evening doing a quick recap. I wasn't paying much attention because Sophie said we could attend one of her and my father's parties on Saturday night. I could fuck more women in one night than I had in my entire life up to that point was how Sophie sold it to me. I didn't take much selling. I did fuck Sophie hard that night; she kept screaming at me to fill her to the brim.