It depends on how humliated your sub would like to be.
I find orgasm denial/cum restriction for me a pain in the ass, and not humiliating, unless that is I have to negotiate an orgasm.
You can have her play all day but never cum, and she is only allowed if she does something that is humilating to her. But you both would have to figure out what activities you both enjoy.

Some humiliating things I have come across are, peeing myself in my underwear, and then putting the underwear in my mouth, and masturbating until I cum.

Peeing a few times in the toilet and sticking my face in it, while masturbating until I cum.

Peeing and using my fingers to wipe myself, and sucking on them.

Peeing in a bowl and wiping it all over her body, and not showering until very later on in the day.
Or having her play with herself and when she is wet, wiping that all over her face and body, having it again remain there for the rest of the day,

Okay enough with the pee,


Have her put food, in her pussy and keep it there for a half hour, vegetables work best, then have her eat them for lunch.
Make her eat them one at a time, or on the floor as a dog.

Make her crawl around all day, with a collar.

Have her play with herself in front of a mirror, with or without toys, after she has cum, she has to describe how she felt watching herself.

Hopefully you can get something out of that.