I think I always knew my mom was wearing thongs because when I was a kid it was normal to see us at home in underwear. In the 1980's thongs weren't so common but she had some. In the 1990's I was a teenager and I started to spy on her when she was with a lover because I knew she wore thongs to excite them. Around 2000, there was this fashion to let thongs showing. She was in her 40's and started to wear obviously whaletails. She's now 68 yo and still wears thongs.