sounds close enough to "on topic" for me!!

As said before had my MIL for a while but never my then wife or her mother in same room, but on holiday we was left alone for a few hours and well we fucked lo, we just finished as the wife and her dad drove in to the villa, enough time for her to slide on her swimsuit and for me to get into the bed , still with cum in her and cum on me lol, my wife came in to " wake me " and well i presented to just wake up, she was sucking an ice lolly and rubbed it on my balls and helmet and licked my cock ( the ice lolly made her tastebuds numb ) then she went down on me taking in all her mums cum and mine,
Few days later the mother told me that as soon as the parents worked out what we was up too the dad had his wife sit on his cock and soon he shot his load and then she made him 69 her cleaning both his and my cum out

Great thread!

Back in high school I dated two sisters. The oldest, J, was my first, and I was the first for her younger sister C.
J and I tried the whole relationship thing, but it didn't work, but we worked really well as fwb. I started dating her younger sister (14 months younger) and at the encouragement of J, C finally let me be her first. While I was dating C, I showed up to her house for a date, and her mom, who was hotter then either of her girls, told me C had gone shopping with a friend and their car broke down and they were waiting for a tow. No problem, mom was cool, so we just watched tv. Shortly after I got there, mom calls me into the bedroom to help her move a dresser, and when I walked in she was naked on the bed, legs spread wide open. I was in shock, but she told me she wanted to see what made both of her daughters so happy.
I found out that J had told mom I was quick learner and had a good tongue. Mom hadn't had any sex since she and her husband had split two years ago, so she was ready to go. I dove in and just after I shot my load into her, we heard C pull into the driveway. It was a quick scramble to get dressed and I made it to the couch just in time, mom jumped into the shower as a cover.
A little history: Mom and her husband were neighbors, and both knew my parents. My parents split about the same time and my dad had the hots for mom.
Fast forward twenty-five years: We all lost contact with each other, and a few years ago I told my father this story and he lost it. He had tried to get mom for years after they split and she always shot him down, not even a date.. He was pissed to know she gave it to me on a regular basis while I finished high school and college, but she wouldn't go on a date with him.
I ran into J a few years ago, had a few drinks and laughs about old times. J and mom knew what was going on, but they never let C know about everything. Seems she was upset about giving it up to me and us splitting up shortly after. But she was the one that broke up with me, so no guilt on my part, outside of me having sex with her older sister and mom while we were dating. LOL
I have another mother and daughter story that happend after the ex wife and I split and I was working as a bartender that I will post later.

Mother/ Daughter/ Grandmother
 

I however did fuck a sisterinlaw of mine and later her mother neither knew about me fucking the other nor did my brother. But I never had my own motherinlaw etc.

Mom then daughter
 

I was 17, my best friend was without his car as it was in the shop, so he asked me to take him over to a girls house that he had just met. He was sure he could fuck her if I let him take my car for a while. The two of them went to the store LOL to pick up some things. I stayed with the mother watching tv. When I started thinking about my buddy fucking the girl in my car, I got a raging hard on. Mom wasn't much to look at but I was so horny I did not care.
I moved over to her, turned her head towards me and planted a big kiss on her.

She really responded so I grabbed a tit, then her pussy. She ripped her panties off, I buried my cock in a very nice wet pussy. Mom was a very good fuck. A few months later my buddy broke up with the girl, I had been fucking mom pretty regular. On one visit mom floored me when she told me her daughter liked me and was needing some sexual satisfaction so would I fuck her daughter. Naturally I went for it. I had both of them till I turned 25. Never did the two together though I would have liked too. Mom wanted me to marry the daughter so she could live with us and we could enjoy each other often.

LOL
 

Yeah, I have. My mother in law is my ex from High School. She is actually living with me and my wife right now. Lots of flirting, wife told me to go for it. Maybe even a 3 some. who knows. right now its lots of flashing, and fun.

So, in high school you dated a woman. Later you married her daughter?