Fun thread with some great suggestions. With the embarassment / humiliation aspect being so important, you obviously feel the need to be "caught" by other people being exposed, not just them seeing more of you than they might ordinarily, but you visibly realizing that that have seen you. Probably the easiest way to do this is a "wardrobe malfunction" like a strategic button on a shirt magically pops off or at least slips through the button hole. You can control where this happens or leave it to chance to increase your surprise.
Years ago a former girlfriend had an old shirt that the buttons would not stay buttoned if any pressure was placed on them. Discovered it by accident late a party one night when I walked up behind her as she was talking with some guy who had been after her for a year or more. As I stood next to her could see his eyes were locked on her chest, but he was always like that so did not pay much attention. As we walked away minutes later I noticed her shirt was unbuttoned way below her bra. As I debated whether to tell her or not [being the good boyfriend or the lusting teenager] another woman did and she buttoned her shirt but did not seem concerned. Later that night she was extraordinarly enthusiastic.
So the next time she wore that shirt I made certain to tug on it a bit and sure enough we had a repeat. For some reason she kept that shirt for years - guess she liked it as much as I did.