Buy some cheap white t-shirts and some permanent and washable markers.

He can write what he likes on the t-shirt and make you wear it in public.
If you use washable he can reuse the t-shirts.
some things to write

"Wink if you think i'm a slut"
"I am not wearing underware"
"I wank too much"
"I swallow"

He can also write on your skin - e.g. "Property of xxxxxx"

He can make you go on-line and show your self to strangers.
He can get you to post a personal Ad proposing sex for money or anything else to humiliate you. With photos if He wants.