Hello, my name is Natalie. Thank you for the opportunity to help you with your question!
An idea of hot to stop bullying is to draw a before and after scene. It can be of something simplistic- like a heart. Before bullying the heart could be small and cute. Then you have two outcomes- one of with bullying and the other without. The one with can be of the heart being broken. The one without bullying has the heart with another heart. The message can say "Why bully when you could be a friend?"
I know this is simplistic, but it would carry out a heavy message to the audience.
If the piece is to how to stop bullying then a good way to to become friends with the bully as they have their own insecurities that they just need to share with a friend to become a better person.
Please let me know if you need any clarification. I'm always happy to answer your questions.