My LO is 20 months and for the last few weeks it's been difficult to get her to sit at the high chair or booster chair to eat. Up until now she's been pretty good and has wanted to sit. Or if she didn't, I could usually entice her by giving her a few bites while out of the chair and then she wants to sit. But lately it's been a huge battle. I don't want to give her toys or let her watch TV or anything. Any other tricks?