I'm having a lot of trouble with the clicking aspect; not being able to click it enough in time and my hands cramping up a lot. So, maybe another way to help them change forms or less clicks?
If you buy a bunch of treats and other items from the store it should help you with that. I mean my hands hurt now too, but with buying things from the store I never had any trouble with those time limits.
You don't actively give them the treats, I don't think. I think they work as a passive boost, as in simply having bought them boosts the amount of points per click you get in the future. Although you're right, I don't think the game currently communicates this clearly.