If you have a brother or a sister, you’ve probably had your fair share of arguments and fights that ended bad. Turns out, things are not much different when it comes to dogs. In the video below, Mac can be seen trying to get used to his younger sister, Lucie. But don’t be fooled by Lucie’s size, she’s clearly the one running the house. On top of that, Lucie likes to play dirty. At one point of the argument with her big brother, Lucie turns around and sticks her butt in her brother’s face (wow, there’s chain of words I’d never thought I’d use).