There are many ways to humiliate a male submissive. If fact, keeping a male sub in a constant state of shame and degradation is a good way to maintain him at maximum submissiveness. Here are some of the basic ideas:
Start with CFNM (Clothed Female Naked Male). A sub must be naked at all times in private. Dommes wear clothes because 1) that's what civilized people do, 2) the sub has no business ever seeing her unclothed body.
Shave his whole body. That's right. Everything. Maybe let him keep his eyebrows. At a minimum, his pubes need to be shaved. No sub is allowed to have pubic hair.
Now give him some accessories. A chastity cage is a must. It controls his orgasms and lets everyone know he a pathetic beta who isn't even allowed to get hard.
Add a butt plug so he can constantly feel his filled up "man pussy." And, of course, he will have his slave collar and matching wrist and ankle cuffs to complete his attire.
A sub must be given an embarrassing name. A dog name like Fido is good. Or make up an embarrassing name, such as Latrina. If you can't think of anything, just refer to him as Slut or Worm Boy.
Give him a steady diet of degradation. Call him a "stupid bitch," make fun of his small joke of a penis that can never satisfy any women, reinforce that he's a loser beta and that only your pleasure matters.
Make him ask for permission to do anything and don’t grant permission easily. Make him BEG.
Give him eye-contact restrictions. He is never to make eye-contact with you without permission. Also give strict speech restrictions and when he is allowed to speak, make sure he use honorifics, i.e. Mistress, Domina, Goddess, etc. If he speaks out of turn, gag him.
Be sure to give him a weekly maintenance caning so his butt remains beet red with fresh, new welts.
The sub must eat his meals from a dog bowl or directly off the floor, and then wash it down with his Mistress's golden nectar.
A sub is not allowed to use furniture, however, sometimes he can be furniture. Subs make nice footstools. If you're a smoker, use his mouth as an ashtray. Also spit into his mouth regularly.
Mark him as yours. Force him to get a tattoo saying "Property of Mistress ______." Make him get a P.A. piercing and nipple piercings. Brand him with your initials.