I added a translation. I guess.

But if you wanted to "translate" you would have written "chirp chirp" instead.

Most of what I see on Danbooru retains the "chin-chin".

Then perhaps you should look more, because I have no idea what that's supposed to mean. Or I didn't, until S1eth said it.

Duly noted.

You know, there is a certain amusing fact to this. Assuming she is indeed saying Chin-Chin, which is slang for penis, lets take slang for penis in English.

We (Assumedly) are confessing our love for Mystia and she is calling us a dick.

Maybe our fly's open.

Mysterio006 said:
Maybe our fly's open.

it can't be that
i'm not wearing any pants