how can slunk be the past tense of slink?
God, they seem to connote such different things. If lady slinks toward you, it’s sexy. If she slunk toward you, it makes her seem kind of dirty or frightening. If a cat slinks toward you, it’s up to clever cat tricks and is in an Aesop fable where it comes out on top. If it slunk toward you, it’s probably about to scratch you and give you rabies.
I guess slinked is an okay substitute, but it’s not grammatically accepted yet, I don’t think. Cormac McCarthy just used slank, which is gross.
Just use slinked. No one will notice. If so, say something about strong verbs having irregular productivity—cite snow surfacing as snew and snown for how wonky the paradigms can be—they’ll believe you.