Winter is a good time to train your sub in the field of public humiliation. What better way to do so then to keep her gagged, and hands bound neatly in front of her hidden by a sweater or hand warmer. Take her to a secluded bar, sit in a corner, order two drinks, make her beg when she wants to take a sip. Gently pour it in her constantly forced open mouth.
With enough practice, she’ll become used to it, and there is no longer a need to hide the gag, just show off what a good girl she is for the world to see.