how kids can defend themselves against bullies

Model compassionate, respectful relationships from the time your child is small.
As Alice Miller, author of Thou Shalt Not Be Aware, wrote: “If children have been accustomed from the start to having their world respected, they will have no trouble later in life recognizing disrespect directed against them in any form and will rebel against it on their own.”

The most effective way to keep children from being bullied, and from becoming bullies, is to make sure they grow up in loving, respectful relationships, rather than relationships that use power or force to control them. Children learn both sides of every relationship, and they can act either one. If you spank, your child will learn that physical violence is the way to respond to interpersonal problems. Research has repeatedly established that physically disciplining a child is associated with more bullying behaviors.

Model confident behavior with other people.
If you tend to back down easily so you don’t make a scene, but then later feel pushed-around, it’s time to change that. Your child is learning from watching you. Experiment with finding ways to assert your own needs or rights while maintaining respect for the other person. It’s also important not to put yourself or your child down, because you’re teaching her to follow in your footsteps.

Practice with roleplays so that your child feels comfortable responding to teasing and provocations.

Roleplay with your child how he can stand up to a bully. Point out to your child that the bully wants to provoke a response that makes him feel powerful, so showing emotion and fighting back are exactly what the bully feeds off. Explain that while he can’t control the bully, he can always control his own response. So in every interaction, how he responds will either inflame the situation or defuse it. Your child needs to avoid getting “hooked” no matter how mad the bully makes him.