Humiliation

You may wish to be treated like a dog, or a pig. You could want to lick my spit from the floor, or eat food that I have trampled into the mud. 
Verbal and physical, humiliation, and degradation from mild to extreme.
The most important thing is consent so when it comes to public humiliation, scenes can be arranged in front of other consenting adults. I will not expose people who have not consented to witness your humiliation.