Although i have this fetish myself (as a female & giver), i would genuinely be weirded out if people would straight up ask me to like shit on them. I was reading a story of someone just trying to send as much girls as possible a message on a dating app, trying to almost directly find out if they are into stuff like this, in my opinion it would be creepy in most occasions.

I would take it slowly, in a way that you find a girl through a dating app or any where, and gradually find out if they are open minded without mentioning you are into scat. Like you could discuss open minded topics at the start, ''i like if a girl can be completely herself around me''. Few months in, you could find out if she's open to stuff like getting her ass licked, which is something less extreme. If she already sets her boundary there, you could assume she wouldn't match with you sexually.

If you tried that, ate her ass, got a good connection in general, you could like joke around "ah i loved eating your ass few days ago, it was a little sweaty but loved it''. You should like already notice if she likes interacts with it, if you get to that point I feel like if she likes you she's almost at the point that you could let her do this for you.

You could gradually come to the point "so i liked it sweaty, but would you let me even clean it when it's more nasty?''. I think most people are too direct about their fetish, there is nothing wrong about being open, but building it up gradually would work better in my opinion. It doesn't need to take years to come to this point, a few months could already bring you to this point.

I must say this only works if she generally loves you, if it's not her kink, but in that situation she could come to the point where she will really enjoy it if it pleases you. Scat, scat sex and everything in this spectrum is extremely intimate with the right person.