I agree with the forbidden fruit concept. When the was young, jeans / dungarees / play clothes were what you changed into when you got home from school because you weren't allowed to get dirty in your school clothes. I remember neighbors who wore jeans and were allowed to do things in them and get grass stains and torn knees when I wasn't allowed. On a hot day, I was playing in my kiddie pool in my yard in my bathing suit. An older neighbor walked by and said that it looked like fun and asked if he could jump in. He was wearing jeans and I asked if he would get in trouble with his mom for getting wet in clothes. He said that she doesn't care. Seeing the wet jeans on him as he walked away seemed so liberating.
As I got older, I started to find myself "accidentally" getting my feet and jeans wet while walking home from school. While on a very rainy camping trip, I saw kids playing football on a rain saturated field. The game became more of a tackle game with kids sliding in the puddles. One kid was actually wearing a pair of light or white colored jeans. I asked if he was going to get in trouble with his mom when he got home and he said that she probably wouldn't care as long as he had fun. Seeing the white muddy Levis got my juices flowing.
To this day, I love seeing wet, muddy, trashed jeans on people. Any type of mess on casual clothes, especially jeans, is an instant turn on for me. It is a very liberating feeling to get wet and messy in my jeans and the possibility that my clothes get stained, ripped or destroyed and not getting in trouble for it.
So much of this thread really resonates with me. It has definitely been stamped on me from a very early age - vividly recall the hyper-arousal of excitement /embarrassment when seeing gunging on TV, long before I could equate these feelings with a 'turn on'. Even where I can't fully re all the show, I remember the images and the accompanying feelings. Sadly these also became bound up in shame - and that can still be tough to deal with.