Brush teeth 15mth

How? My gal fall asleep after milk before sleep. I try to brush or flash water she will wake up and then we need struggle for another 1-2hrs before she fall asleep and sometimes need more milk to sleep. . how do you all brush your baby/toddles tooth?? I try to give milk then bath but she always fall aslp while drinking n if I wake her she cranky. . How to brush her teeth?