https://civitai.com/models/427073/throat-fingering-mouth-play

Good for testing gag reflexes or throat training. Fingers or hands deep in the mouth like there's a bonus clit back there.

Trained with the phrase hand in another's mouth to benefit from prior knowledge, and to improve the ability to interact with existing prompting. It generally works best with that in the prompt, but also will improve the existing prompted tags like fingers in another's mouth or work with prompts that reflect the concept.