... don't have to be public things, nor do they even have to be physical acts. You can verbally humiliate someone and they probably won't even realize you are doing it. Hell, you probably won't even realize you're doing it.

Anytime you call your girl a slut, that is humiliation. Anytime you deny her clothing or make her ask to take a bathroom break, that is humiliation, BUT it is also discipline by giving out privileges. (See "Rose Takes a Day Off" for further) Telling a girl what a stupid piece of shit she is is humiliating, yes, but it is not humiliation, it is degradation and should be avoided at all costs. It does nothing for your submissive but make her feel like shit.

Humiliation is supposed to make a girl feel more submissive and more open to you. It is also used primarily to remind her that she is lower than you and what her position in your relationship is exactly.