Much of the rush of public humiliation is a product of the mind.
I can remember the first time that I was ordered to wear panties under my clothes when we went out shopping (panties have never been a fetish of mine and they still aren't to this day). This was very early in my first D/s relationship. I didn't want to do it but I got a warning of what would happen if I didn't so I didn't offer much resistance. My mind was racing around about it and I was feeling incredibly self-conscious. This was really one of the first major mind-fucks I ever received. I stayed relatively quiet while we were shopping and after a while Mistress started whispering things in my ear.
"She knows you're wearing panties."
"They can all tell you're a perverted panty boy."
"See that girl over there? She's looking at you funny, I know that she knows."
Each time she would say something it would make me blush profusely and I was getting pushed deeper and deeper into subspace... even though I knew what she was saying wasn't really true, my mind was so clouded that it was as if she was speaking the truth. The deeper I found myself in subspace the more turned on it made me and soon after she noticed the bulge in my pants and the comments happened more frequently and there were even some threats about shopping for more panties for me that day since she liked what it was doing to me.
Several years later while I was with my second Mistress I had a similar type of rush in the mind. We had been out shopping and found a pair of pink gloves trimmed with pink fur that she was going to make me wear. Later in the week she ordered me to go to the store with the gloves and find a matching hat and sweater. Matching = must match perfectly. Perfect match = I would have to bring the gloves with me.
This was ordered as a solo trip so I went off to the mall that had a few stores we would often shop at together. I had the gloves in my coat pockets and when I first found something that I thought was similar, I found it was incredibly difficult for me to take the glove out of my pocket to see if it matched. As I was about to do it for the first time I was hit with this incredible paranoia that was similar to the panties trip, it felt like I was surrounded by other shoppers and that all of them were paying attention to what I was doing (and assuming that I was shopping for myself and not for a gift). I would kind of go to a secluded area to compare and I'm guessing I must have looked a lot like a shoplifter. Luckily, the hat was easier since I found one of the same brand from the same collection and knew it was a perfect match.
I believe the trip was ordered since she knew I would feel that way and she asked me to tell her about the trip later.
Isn't it odd how there doesn't have to be any real humiliation to feel humiliated?