In your example of double pronouns it is clear that the two pronouns both go before the verb: Example 1: Je me brosse les dents -> Je me les brosse
I’m brushing my teeth -> I'm brushing them
Example 2: On the same page you have: Tu te les brosses toutes la nuit.In the first example - unlike the second - there is no ‘s’ after brosse when using les as a direct object pronoun?