When Remus came out as non-binary, they spent much of the following month explaining what it meant.

"Gender is a spectrum," they would say, "and I'm somewhere in between male and female."
But those words didn't seem right to them.

So they tried a different way: "Male didn't feel right, and I know I'm not female, so logically I had to be somewhere in between."
It was closer, but it still wasn't right. It wasn't a case of not fitting into the binary system that made them non-binary. It wasn't anything in particular. It was just a word to them. One that explained who they were.

Later they explained things differently again.
"Imagine that the words 'straight' or 'male' don't really exist in society. Imagine they are a whisper of possibilities that aren't really used. Imagine everyone you meet is gay or non-binary. Bisexuality exists, but it's just another whisper, stronger but a whisper all the same. Now imagine that you don't fit into what society tells you is normal. Imagine you like someone of the opposite gender or you fall into what could be called a gender binary. And then you find the word: it might be 'straight' it might be 'female' it might be 'male'. But whatever it is it fits. It works for you. You have a sense of belonging after all of these years of feeling like an outsider. There are other people like you and you aren't just making it up. Now imagine that what I have told you is real, and you will get close to what I've been feeling."

Remus knew it didn't explain why they felt the way they did, but it helped other people understand a bit better about why they chose to use they/them pronouns.