I´m thinking like this: If I have TPTK on flop I bet pot-sized (partly) to scare straight and flush drawers away. Four-to-a-flush and open ended both have ~1/3 of getting their card on either turn or river, so heads up, they have incorrect odds to call.

But on the turn, what do you bet when you still want to scare them?? They now have only ~1/6 chance and the pot is pretty big. So a half pot sized bet should be enough to give them the wrong odds? How do you do? Betting pot sized on the turn with top pair could be pretty expensive...