"nstarp" is enough to generate. With prompts "nipple piercing" can better generate more similarly as training materials. It's just that the strange texture of the ring can't be avoided anyway, and the stars become opaque.

And "piercing" trigger "earrings, ear piercing, navel piercing", if you don´t like them (I didn´t add these), just put these in negative prompts.

(Civitai doesn't ask you to post an image to evaluate a model anymore, therefore your fetish won´t get exposed by giving reviews or clicking like. Just remember to clear browser history and logout your account regularly.)