I developed a panty fetish at an early age. The first phase was with a sitter, an older girl I had a crush on. When she was napping, I stole a pair of orange nylon bikini panties from her drawer. These became a favorite jack-off aid. My next foray was thieving a pair of her worn cotton panties from the bathroom hamper, added to my collection. Eventually she caught me, squatting on the toilet, furiously stroking my cock with a pair of her panties, filched from the hamper - I'd forgotten to lock the door... she burst in, catching me red-handed. After that incident, the teasing and derision she held over me was unbearable, blackmailing me to stroke while she watched, telling me what a naughty, dirty boy I was. That came to an end when her family moved away.
My next experience was with an older married woman (older in the sense she was in her early thirties). I did odd jobs for her. I developed a serious crush on her as time passed. She eventually took me, my first real lover. The genesis was being caught in the act, after filching a pair of her panties. She saw the waistband peeking out of my pocket, where I'd tried (poorly) to conceal them before going home. Lois was an extraordinary woman, kinky, perverse and totally depraved. She taught me everything I know about sex, and how to be a good lover. Lois used her insight into my panty kink/fetish as a means of control and torment.
Now, my wife KK uses her insights in a similar way, exploiting my thing for panties, nylon, stockings, lingerie, and heels to sexually stimulate and torment me. KK has a litany of derisive commentary on the topic; "panty bois," "panty stealers," "panty wankers," and so on. I've been caught with KK's stolen panties, jacking my hard cock on, or with them too many times to count. I have a secret collection of panties from many of the women I've been with, all the way back to that first pair of orange nylon panties I swiped from my baby-sitter. They are a treasure-trove of jackoff fodder.