We do the same EXACT thing as you. Whether that is good or bad, I dunno, but I feel the same as you about pinning her down will give her bad association and she will not want to do it at all, whereas now she actually enjoys brushing her teeth and I let her do it whenever she feels like it (which is usually a few times a day) and I will put Tpaste on the brush at least 2 of those times. Ocassionally I feel diligent about trying to help her pay more attention to the front teeth b/c she has a geminated tooth, but that is my only concern b/c it is easy to get cavities in those.