Now I’m not sure if a ball (or bit) gag is a fetish or a bondage attribute. It does not do much for bondage: you can push or roll it out and you can speak (unless you pull it very-very tight, but virtually anything can become a bondage item if you make it “very-very tight ;-).
The photo on the left is about pure fetish, no bondage at all.
BTW, see Lipstick fetish forum thread.