The learning experience [mf]

It wasn’t a very good secret I could always tell something was going on, they just always wanted to hang out and seemed way too close.
So for a few months I just got more uncomfortable with the whole situation m, and then they started hanging out without me there, didn’t ask me if it was okay not a care in the world of my opinion and that was the last straw…
The guy who she was hanging out with seemed to have forgotten that I had been to his house a lot in the past couple years, he also hadn’t known what his mom had told me, well actually more hinted at… she was in an open relationship and often flirted with me, but I was 18 at the time still learning the ropes and honestly thought really nothing of it.
But then after all the events leading up to this I took it upon myself to explore just how far she was willing to take that flirting, I started flirting back joking about stuff I’ve done and stuff I’d like to try and wouldn’t you know it she liked all of it.
She was 46 at that time 5ft ish and 100 pounds maybe sooo I guess you could say it wasn’t a hard choice what was gonna happen next.
In the most Michigan story we had to run to Meijer for stuff to eat for dinner the guy and my gf said go on and help her shop, I knew they probably were gonna do stuff and I didn’t care because I planned to do the same, in the parking lot she joked and said “are you just gonna finally kiss me or not?” I really wasn’t ready for how forward she was but I wasn’t gonna turn it down, it started with a kiss i laughed and said “ back to 8th grade stuff huh?” She came back hard and started making out with me and damn was it fun it probably didn’t last and long as I remember but eventually we did have to shop, skip ahead a few hours and she kept smiling at me while cooking and eating and then watching a movie, after the movie ended like it was meant to happen my “friend” and “gf” wanted to run to the gas station I said I’d stay and help clean up dishes and you can guess how that went.
I finished dishes and turned around and she asked me to come to her room, she showed me a few toys and asked if I wanted to see how to use them I of course said yes and watched her start using them on herself then she asked if I wanted to try which I didn’t even reply to I just hopped on her bed and she guided me around, in a way teaching me stuff I’d later use all the time I’m future gfs and then it was my turn to undress and she definitely took charge and showed me everything and made like work twice on me aka still only like 20 min of actually having sex but damn I still haven’t forgotten.
The not so fun turn in this story is when her son aka my friend walked in the room and caught us laying there naked, it was obvious what happened and I told him exactly what happened “ you fucked my gf and now I fucked ur mom” I looked at her said thank you for an amazing time and walked out.
It quickly spread around school yes (high school) but I was a senior she knew I was 18 so nothing came of it except a lot of low key high fives and jokes about not messing with anyone I dated ever again