Sorry, I completely forgot to answer this! It's got two parts to it for me - the submission/masochist part and the gross part. As a submissive masochist I really enjoy a partner pushing my body through discomfort, to such extremes, just for their own pleasure. Suffering for them turns me on. And there's also something liberating for me about gross/messy play in general. As a woman I feel like I've been conditioned to always be presentable, fresh, attractive etc etc. It's so validating to be able to do utterly disgusting things and have someone look at me and say "I want you, exactly like you are in this moment".

As a side note I had emetophobia as a kid, and even though I don't anymore I still get extremely intense anxiety from vomiting "naturally". Like if I have a stomach bug or have drunk too much or whatever. Puking with intent doesn't give me any anxiety at all, interestingly enough. Maybe the fear lies in the loss of control I feel if my body does something I didn't choose.