I don't always have the best memory for what I've said online as opposed to what I've read, but to the best I can remember, I find myself using "special interest" for past perseverations and "hyperfixation" for current ones. I think... I think "special interest" doesn't sound as intense as what I feel when I'm currently perseverating on something? Also, as I am finding in the process of writing this post, "perseveration" and "hyperfixation" both have handy verb forms; I can't very well say I'm special-interest-ing in something.

(Do other autistic people go through a bunch of special interests in a row? I'll see people say "Trains are my special interest", but I'm more like "I had a huge special interest in sailing ships when I was X years old, so of course I still know a/b/c things about them". Or is that more likely an artifact of me having the near-eidetic memory?)

Edit: And by "post" I meant comment, of course. Side effect of the new job.