Take an episode (or just a scene) and re-write it with all the characters (or just one... say, Lex) having been sprayed by a truth potion / perfume, so that instead of lying to each other they can only speak the truth.

Writer's choice if the "truth" means Clark type of double-speak (where he leaves out enough detail that he's still strictly 'not lying') or if it's 'the whole truth and nothing but the truth'.

Ooooh, I like this idea!

Let's see how that would pan out. Like this , maybe?

Perhaps. Imagine PML with Revenge as a truth serum instead of a love potion.

It wouldn't be unlikely for something that lowers your inhibitions to also lower the ones about keeping secrets. So it could be both with animal tests not showing the truth part.