I decided to describe the events sequentially, and what led me to this fetish (Mathew Elizabeth described and structured it well, I will use it as an example)

My mom was definitely one of the most beautiful women in our city, I won't name the city and country, but it was all in Eastern Europe.
As for her appearance, she dyed her hair in different colors, her natural brown color, her face was very symmetrical model, with big gray eyes.
Figure one of the features is a large natural breast, with a sporty toned body, even with age she kept herself in shape and keeps, and she improved her ass with the help of training in the gym, but that was later, in 2010-2012.

at the age of 10, on vacation in another country, she was molested by a young guy about 20 years old, it was the first time I saw someone openly flirting with her standing next to me, I didn't bother him at all, she, of course, ignored him and left with me.
But it was on vacation that she dressed extremely sexy, various types of swimwear that accentuate her figure and that attract men's looks, she liked to show off her sexy body, I still remember how she walked, and her tits bounced with every step.

When I was about 11 years old, I studied at one of the schools in my city, it was a good educational institution, I come from a prosperous family, but at that moment there was critical situation, a lot of bandits, poverty, and, of course, people were different, from different backgrounds, I don't know how in USA, but both rich and poor could study in the same school.
So, one day my mom came to school, she was wearing a jacket and shirt, a knee-length skirt and high-heeled shoes.
These clothes emphasized her figure, walking down the corridor with me, the local punks stared at her and looked at her for a long time, it was the local hooligans who dreamed the nightmare of our whole school.
A little later, after my mom left, they came up to me and asked: "Who was that?, is that your mom?" I answered "yes", one of the boys said "Wow", I remembered it, his eyes were round and his mouth was half open, on a stupid and rather rude face, after that I left.

Somewhere at the same age, friends came to me to play a game console, my mother sometimes played with us, at that time she was about 32-34 years old, and she had no problems contacting us if she wasn't doing something and she had free time, and at one from those days I really remembered and remembered it very much.
One of my friends invited her to sit down to play with us, she sat on the sofa, between my friends, I also sat next to her on this sofa, but this time my mom was wearing a loose T-shirt and shorts, they showed how to play the game, and touched her body when it was possible, snuggling up to her from both sides, they also corrected her, constantly holding hands. And then I looked at her T-shirt, her nipples were sticking out very much through it. Her nipples often stuck out through her clothes, this was due to a change in temperature, and it is obvious from the contact that she felt it herself and said something in the spirit of "okay, I've played enough, I'll go do my own thing" and went to her room.
My friends pretended that nothing had happened, but I saw where they were looking and how they snuggled up to her during the game, while I, in turn, did not know how to react to it correctly, and also pretended that I did not see anything.
During the same period, my mother helped my aunt with business, they ran a store page on social networks, she carried various branded underwear from other countries, and as for advertising, her sister asked me to pose for my mother in underwear. I heard about the dialogue, and she very reluctantly agreed, one of the conditions was to somehow hide the face, that is, only the body, they hired some photographer, I do not know what and how, but the photos were taken, they were quite simple in terms of poses and light, and processing in Photoshop, but not bad at the time. So, my aunt had a son, I saw him very often, he was a nerd, let's say, and maybe even autistic, since his actions were very often strange, he asked me somewhere after the photo shoots:"You saw your mom, I saw her naked in photos," he meant in her underwear, but at that moment I was very outraged by this question, I answered him: "Of course, I saw her bathing in the shower," and this is partly true, I actually even I swam with my mom a couple of times, but there were situations when she was in a hurry, and it was at a resort in another country, so I saw her completely naked from all sides, I even had a boner..
Then my cousin said: "And I didn't take a shower with my mom, can I take a shower with yours?" I immediately replied to him: "Bathe yourself idiot." It was a very stupid dialogue, now I laugh at this shit, but then I was angry and wanted to smash his head.
Then I found the store's page on social networks and tracked down who put likes, it was my father's acquaintances and, to my surprise, my friends.... and classmates. I was in awe and rage, I wanted to beat them up, I didn't want them to even think about something, but I couldn't influence it, they wanted her, and that was fine, because I myself was the same, just specifically I was lucky and unlucky, at that time at the same time, a beautiful woman is nearby and so inaccessible, while you see many sexual aspects of her personality
Somewhere at the age of 12, the history of judo begins, there was a certain conflict, the parents talked to each other and decided that we should stand up for ourselves, since our mother gave us a ride (she drove us by car and waited for about an hour on the bench) at some point she came up with the idea to train with by us. She talked to the coach, he didn't really mind, adults came there, including women and girls, but there weren't very many of them
So, there were a couple of guys who were clearly from dysfunctional families, they were constantly talking about girls, well, it was clearly fantasies, they exaggerated a lot, they were telling obvious lies.
And then one day my mom paired up with one of these boys, the beginning of the workout was that after jogging, warming up, people split into pairs and fought in grappling, and each time they changed after 5 minutes, and so it was about 3 times.
One of the boys was obviously just taking advantage of the situation on the ground, my friends and I were looking at my mom during the fight, in general it was very distracting, but the way she fought was an exciting sight.
Then my friends told me, "this boy has become completely insolent, he clearly does not fight with her, but rubs his head against her body," I experienced terrible embarrassment, I did not know how to behave in such situations, but then a strange feeling of excitement intensified.
A little later, maybe a month or two later, she got into a fight with this guy again, and during the fight he seemed to push her away from him, pressed his hand to her chest, it even seemed to me that he squeezed her a little.
And then I was standing behind the wall in the locker room, listening to what he was saying about my mom, he was bragging to the guys that he grabbed her breasts in his hand, and about what her overall shape was, I also heard others say what to do with such tits, but I remembered one answer "I I would suck and bite them," when I entered, they all fell silent, abruptly changed the subject of conversation, while my mother behaved quite friendly with them, she clearly did not understand all these contexts of events, she had an attitude like children, that is, she clearly did not understand not to perceive them seriously
And my friends wanted to see it with their own eyes, and they themselves were not averse to practicing with her, but, unfortunately for them, this did not happen.
During this period, I very often heard all sorts of things about my mom, my friends told me about it, what this or that boy could say about her in the locker room, there were a lot of fantasies, lies and nonsense. The coach, by the way, flirted with her, but she politely refused him.
And one day my mom was warming up on the mat, and she was attacked by a crowd, it was probably the only time she was embarrassed, and after that she stopped going there, she realized what was wrong, she pretended to be funny and funny, but she was insanely embarrassed, well, boys, they just held her by her legs, by her hands, and when she struggled, it was clear how her hands were sliding where they were not needed, someone on the contrary pressed her closer to him, she laughed and pretended that it looked like a joke, then she abruptly stood up and left them Holding back the anger, it wasn't a long event, It was all fast enough
I saw that the boys were very happy, it was clear that their hands were where they didn't need to be, later in the locker room one of the boys boasted that he ran his fingers over her nipple, I remembered it very much, and friends told me the same thing later, they wanted to beat them, lol I also wanted to, and after that incident I literally destroyed them on the carpet, it seemed to me that I was fighting for the honor of my mother, but again, they could come up with a lot and fantasize, since they often carried all sorts of nonsense before all these events
I still remember how they boasted and said about her, "she has such a long and hard nipple," "I wonder if she gives in the ass," "sucks probably like a vacuum cleaner," these are the dirtiest things I've heard, many things were related to her breasts, perhaps it was just the most accessible place, let's say, and for some reason I remembered "I wonder what color her nipples are."
Then my mom stopped going to judo, She just drove us back and forth

There were other events, but they are not so much worth asking them, I could come up with something and lie, but I don't want to do it, I don't see the point in it, or there were events with me and my aunt, but not with my mother, so I don't see it makes no sense to write about these events specifically, a little later I will tell you a couple more events with my mother, but they are very short.

p.s p.s. this is how I should have originally arranged and written everything, instead of fragmentary information, a little later I will also write down the events about those I have already written about, but it was completely incomprehensible, my English has now become a little better, but there will be errors in the text, I'll just add the events to the same post

thank you for posting

It was rather weird. The day that I graduated high school, I came home and was looking through some photos, in those old photo store envelopes, before things got all digitized. Those envelopes had been there for as long as I lived in that house, since I was a very young child, but I never bothered looking through them. The photos weren't any thing special, but there were a lot of negatives in the back of the envelope. I got curious and decided to squint closely and look at the negatives. It was a woman being photographed fucking different men, wearing lingerie and fishnets in some pictures. After a while I realized that it was my mother and my dad was the guy filming, and I immediately took the negatives into my room and had the hardest fap in my life, I have literally never been able to cum so hard again. Several different emotions flooded through me from wanting to fap to anger. I kept myself shut in my room for a few days after, not talking to my mom. Eventually I confronted her about it and she just flat out denied it...lied straight to my face. I felt very humiliated at the time, as a young boy, so I took the negatives and disposed of them somewhere far away. Now I can't help but wonder if they're still out there somewhere and if I'll ever be able to find those photos in my life. I'm thinking maybe one of the guys that fucked her may have copies, but I have no idea who the men were..I sort of wish I made copies of the photos and uploaded them online or something. I'll never know now..

Saw lot many posted here with stories,
I am not very good writer but I got into fantasy from real life experience after i saw my mom.
Still haven't confronted her about it.

What did you see her do, fuck some guy?

I think for me it was culmination of 4-5 things which happened across my childhood till puberty. I will try to arrange them in chronology and keep it as coherent as possible. While growing up I have seen my mother nude as well as her private parts around 4-5 times. When I was 8 years old I was sleeping across at her feet and she was wearing a gown. During night out of curiosity I peeked inside and was able to see her shaved pussy. She woke up and realizing this and I was jumped out in fear. My dad tried explaining me about this next day but that's all. Our bathroom had a hole in between like a peephole so while bathing my mother used to sing. 2-3 times I have peeked inside and I saw her sideboob and bare back. Another time when I peeked inside I saw her drying herself and saw her completely nude especially her bare ass which eventually made me an assman when I connect the dots.
Then we changed cities and came to a metropolitan city. Here my mother changed her wardrobe kinda completely. She started wearing these tight yoga pants and sarongs while at home. This used to show her ass curve very prominently and bring out shape of her thighs. My friends of that time always wanted to come to my house but I did not realise the reason then. Now I understand the reason. She bought these g-string type thongs, fancy panties and pushup bras. And when used go to market these panty lines could be seen by everyone.
At 14-15, I used to cross dress while nobody was at home wearing my mother's bra and panties when alone at home. I was a scrawny kid short in height, thin, having specks but good in studies. However I had big ass compared to my frame which people used to bully me for. however my friends very athletic and much more strong then I was. My mother always used to enquire about their romantic aspects of life, whether they have any gf's of or not. however when it came to me she used to jokingly say, you focus on your studies as all these things are not your cup of tea. Also, while conversing with my friends she used to very free and open to conversations even to the adult topics however used to scold me for talking about those things even though I was of same age.
Also one of this friend once while in school during a pee break peeked and saw my dick and his of friends bullied me by saying your dick is so small and laughed. However I did not tell my mother about this.
Their were many other things and but these were the triggering points I feel. Then when I went to college I came across bluevelvet's tumblr blogs in 2013 and then this fetish/cuck kink started snowballing and it has been around 8 years now.

Yeah I could see you getting into this fetish this way. Spying on your mother nude must have been hot, and then starting to dress like a slut as you got older must have also turned you on. It did with me with my mother. Someone who you thought was just an innocent woman who never had sex starting to dress like a whore. It turned me on so much when I saw my mom wearing a g-string for the first time.