Nominating the bawdiest dialog from a pre-Code film is a fool’s errand — it’s a crowded field — but this exchange, from Ernst Lubitsch‘s sparkling, smirkingly amoral Trouble In Paradise, has got to be a contender:
If I were your father, which fortunately I am not, and you made any attempt to handle your own business affairs, I would give you a good spanking – in a business way, of course.