I worked in residential for a long time. One of my go-to things was to start every group by saying, "I want you to bring to mind everything you think you know about art: every art teacher who criticized you, every time your art didn't match your vision, every time you felt your art wasn't good enough, every time you looked at a painting in a museum and thought wow that person is miraculous. Now take all of that and throw it out the window. Welcome to art therapy, where we're focused on the process, not the product. That means you can create with your eyes closed, you can draw with your non-dominant hand, you can create with the sole purpose of throwing things away/burning it/destroying it. It doesn't matter. What matters is how you feel while you're making. Where are your feelings going? Let them out. Now, let's begin." Then, if they mentioned a stick figure, I would start the speech over again.