Seems pretty straightforward… Teach it like we always have, and then just add a quick, “the traditional contraction expands into, ‘should have,’ but recently, ‘should of’ has become popular colloquially despite the apparent error.”

Or something like that, I don’t know. It’s not like English doesn’t already have a billion exceptions to every single rule. What’s one more slang term?

Do I like it? Fuck no. It sounds/looks bad, and I will probably silently judge you if you say or write it lol