An answer!

As a they-user, it can get sooo tiring and frustrating to correct people, especially when they don't even realize they've messed up. Strategies I have used (and this may be a couple-tweets):

1: interrupt them loudly to correct them! Ummm > https://twitter.com/EmmaSManning/status/1319013515575894017

> that obviously doesn't always work for various reasons (it's considered rude (but so is misgendering!); maybe they're your boss?; they often don't even notice that I tried to interrupt unless I'm REALLY loud) so...

2: wait until they finish their sentence, and ask them what >

> pronoun they just used. they often don't know, but if you do this enough they'll hopefully start noticing? (It took about a year for me to 'train' one colleague to actually notice their mistakes this way)

3: some sort of clicker or bell? is this mean? I fantasize about it >

> But ultimately, this is on them, not you. What I do is keep count, and start escalating the issue in writing, until I start edging on "um I'm going to have to file this as harassments" territory. Shouldn't be necessary but sometimes is, unfortunately.

Oh, follow-up! For non-colleagues, like just friends, escalating the issue in writing does sometimes also become necessary, but obviously you're not going to go to HR about it. I usually communicate some level of "this is a serious boundary you keep stepping on, it's hard to >

> maintain this friendship with you when you say you want to do better but you keep doing this thing that hurts me. I really need you to actually start showing improvement, because right now it's kind of painful to interact with you." And then you gotta... enforce your boundary