Expository dialogue techniques that don’t rely on characters randomly explaining things to each other that they should already know, but do rely on your characters being obnoxious gits:
1. Character A fucks something up hilariously; character B upbraids them at great length about exactly what they did wrong.
2. Character A wildly misreads a situation; character B corrects their misconceptions.
3. Character A tells a complicated and implausible lie; character B points out the obvious holes in their story.
4. Character A can’t find their destination; character B provides rambling and discursive directions.
5. Character A has a straightforward question; character B requests a series of extremely pedantic clarifications.