Should work on base and edit both. Strength of 1.0 works, plus minus a bit also works great.

Follow the prompt framework for best results:

woman has a [color] silicone-lip gag in mouth fastened with [color] straps, (optional: teeth visible)

EDIT: It can do a face harness too if you use the prompt for a strap as "...fastened with triangular face harness [color] straps"