Simply tell them it is time to brush and take one at a time into the bathroom and make conversation with them while they brush. They will enjoy a little alone time with mom and the job will be done and slide in the next kid.
If they fight it, just plug ahead like you don't notice the fit and wait it out while they brush. Tell them as soon as you are done, we are going to watch XXXX on TV so let's get moving.
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