It started when i (a guy) was around 15 years old (mid 2000's for me). I started noticing that the girl's clothing were getting tighter and sexier, and in a few cases i saw thongs, the usual way. But there are several "thong events" that stuck with me and defined what i do like in a woman's clothing and body. It made me an ass man for sure haha.
- The first i remember was a friend of mine, we'll call her S. She was chubby but had a nicely developped body, and was quite cute. I wasn't really interested in her as she was quite a mess on the personal level (she had several "teen pregnancies false alarms", meaning no protection during sex. Yikes!), but during the 8-9th grade she started dressing somewhat sexier. At that time, it wasn't the leggings/yoga pants craze. Almost all girls were wearing really tight bootcut slacks when they didn't wear jeans. And these kind of pants were really amazing, as they were really tight on the ass and thighs, so the girls had no choice but to wear thongs under them, and as these were made for young (15 to 20) women, they were designed to be quite cheap so they were made of thin fabric. So the only way of avoiding any VPL or VTL was going commando, which i almost never saw happen. My friend started wearing them, but at first she had VPLs. After a few months of wearing these pants, which were black, i noticed she didn't have VPL anymore so i kept an eye open. And my patience paid off: i saw her whaletailing one day, a good 5 to 10 centimeter of the thickest thong i've ever seen to this day, so thick it might have been fullback panties wedged into a makeshift thong. I was speechless, and i kept looking for her slips. They happened every now and then, and they always were a highlight of the day. Always thick thongs, as it seems she ended up getting proper thongs after all. And they almost always showed very clear VTL. Since then i've been into really tight and thin slacks, thick thongs (i find g-strings to be boring) and VTLs, thanks to S.
-Another one, we'll call her A. She was quite a brainiac, always had good grades, but not really nerdy. She was nice and quite hot. At about the same time as S., she started to dress sexier too. But she took it to another level on one occasion. She had those tight white slacks, like the one i've described above. They were so see-thru i've always wondered if she hid them in her bag and changed into them at school because there was no way her parents would've let her go out dressed in them. She wore them several times, but with fullback panties or boyshorts. She had a nice ass so it was still quite a sight. A (girl) friend of hers must have told her they were see-thru or that she had VPL, because she started to wear thongs. Someday, she came in wearing these white slacks with a white thong, which was visible both front and back from at least 10 meters. At first i thought she didn't know, but a guy in my class told her "hey A, nice pants and nice thong!" and she just laughed. She wore them a couple of times after that, always with a white thong (i wish she had put on a black thong at least once to push it further, but i never saw that happen, sadly.) and a short top, so she very well knew.
-Back to S. now (the first girl). During the summer of the three years we were friends (friendship ended because teen drama), we were hanging out quite a lot with mutual friends, and as teens living in the suburbs of a european capital city, there was not much to do. So when it was hot outside, we'd have waterfights. There was an isolated fountain with water jets in our town, so we ended up always going there to have some fun with no disturbance. She almost always wore these crop tops, and of course the slacks with her VTL inducing thongs. Once she had what i call an "almost thong slip" (just the top showing, as if she had fullback panties) and she had some sort of animal printed on them, and a friend of mine said "hey, nice whateveranimalthatwas panties!" and she replied, almost offended that he thought she was wearing fullback panties: "This is a thong, but thanks". But the hottest thing, for me, happened almost everytime we had these waterfights: water made her pants stick to her skin, and showing her VTL like crazy. So i always put her under the jets butt first to admire her pants absorb the water and stick to her thonged ass, it was great. She even said several times, as i put her under the jets, "damn, this feels nice". She also said that sometimes when she was alone she did this too, it was a nice thing to imagine. As you might have guessed i'm also a huge wetlook (wet clothes fetish) fan, so i keep very fond memories of those times.
-Last one: There was this girl we'll call O. She was overly sheltered by her parents, and she was seen as the nerdy girl by everyone (as far as i knew). As the other two girls i spoke of, she started to emancipate herself by dressing quite sexy. Or at least trying: let's say that this period of time will not be remembered as her finest hour in regards to clothing haha. She had her first boyfriend, and they were making out on the benches near our school. That day, she was wearing a quite conservative knee length white dress. So not too tight, not to short, not see-thru, almost the kind of dress you'd expect someone to wear to go to church. Except for one small thing, of course. As i said they were making out on that bench, and she was on his lap, facing him, legs going both sides, almost as if they were having sex. Her dress was a bit getting in the way of her legs of course, so she raised it a bit, but it still was hugging her butt very tightly. White clothes are almost, in my experience, at least a bit see-thru, and seeing her in that dress without any hint of VPL or VTL before made me think it wouldn't be see-thru. Guess what? It was. The fabric was hugging her cheeks and as it was stretched, i could clearly see her nice ass encased in a white with red trim triangle thong (a bit like a VS V thong). I would've never imagined she was a thong wearer, and even less the sexy kind she had on that day.
All these are engraved in my mind quite clearly, and made me the thong lover i am today. Well, that and my first girlfriend who always wore thongs under low-rise pocketless jeans (that's a story for later, maybe).
Sorry if i was a bit long on my descriptions, but i really find it better when there's as much info as possible, so i figured i'd go crazy.