I'm at my wits end, i cannot brush my toddler's teeth properly. Not because she tries to fight me, but because she will not stop biting the toothbrush/pushing it with her tongue or pulling her top lip over her teeth. It's a subconscious response I know, but this is what makes it so difficult to mitigate. I've tried opening my mouth wide but she won't copy me. Any tips, please!? She's 18 months.