Gryffindor/Slytherin: You idiot! You wet the toothbrush before toothpaste!

Slytherin/Gryffindor: No, you moron! You wet the toothbrush after toothpaste!

Ravenclaw: Water dilutes the effects of toothpaste so wetting your toothbrush is never a good idea.

Hufflepuff: Can we just brush our teeth the way we want?