Sleep and eat
Have your slave sleep on the floor, in the bathroom, or in the dog house. Also, have him address you in the third person using your favorite nicknames. He's not worthy of first-person pronouns after all.
At mealtime, be sure to give your slave only leftovers. He can eat them off the floor without using his hands, like the animal he is. If you eat at a restaurant, be sure to order for him and choose an unsatisfying and humiliating meal (children's menu).
Begging is essential
Every time the slave wants something, he has to beg for it. His only purpose is to serve you and please you. Therefore, give him creative tasks that might unlock his chastity cage. Of course, always extend this time as much as possible.
Have the slave shave his legs and pubic area. Afterwards, he should apply a woman's lotion and return to his household chores. Washing your delicates or polishing your boots are always good little chores. You can also have him carry you, or ride him like a pony. He can serve as your furniture or do you a favor in a non-sexual way, varnishing your toenails or massaging your sore muscles.
Public humiliation is where a little ingenuity is required. You can't really humiliate your slave in public like you would in a private setting. If there are people around you, always remember that, unlike you and your slave, they did not sign up to participate in your scene. Therefore, they have not given their consent.
So try to limit your public humiliation to semi-public or private places that only appear public. Don't expose misguided and uninformed passers-by to your perverse world.
Humiliation on the go
Silicone Chastity Cage
Have your slave wear lingerie over his chastity cage, then have him wear regular clothes and send him to the store. Write her a list of humiliating items. Have her buy tampons, extra-small condoms, cucumbers and eggplant with lube, and more.
You can also tell her to buy remote electrical stimulation accessories. Have him wear the electrodes and his chastity cage at work or in public, and turn it on without warning. Torture him as much as you can. However, be careful not to interfere with his personal or professional life and always make sure you get the go-ahead for these actions beforehand.
Keep your slave on constant alert. Have him take a picture of his caged dick and have it serve as his phone wallpaper. He'll need to maintain constant attention if he doesn't want vanilla people to find out about his poor situation.
He's the Cinderella of the house.
If you have friends who are as kinky as you (and therefore willing), invite them over for dinner. Ask your slave to serve them naked or in an outfit of your choice. He can do it on all fours with nothing on but his cage. You can also leave him in the room, gagged and exposed, while you chat with your friends.