My heart goes out to you and your son. As you have most likely noticed, teasing and bullying behavior can have very large and powerful negative effects on the child being teased.  They often suffer from emotional and behavioral problems as a result of being targeted by their peers. Thus, it is very important that teasing is taken very seriously and you and your son's school work together to put an end to the harassment.

First, I would suggest that you talk with your son's teacher to learn more about the school's philosophy and approach to managing teasing behavior. Do they have a documented policy on teasing? Over the past decade, many schools have implemented peer mediation teams and other anti-teasing approaches. Depending upon the school's policy, you should pursue the most direct approach to intervene and stop the bullying. Sometimes, teachers will talk directly with the children who are teasing and their parents. Occasionally, it is escalated to the vice principal, etc.

Finally, you should talk with your son about strategies for managing the teasing in the moment. Help him to develop effective ways of telling caring adults on the playground about the teasing so that he does not come across as "tattling." Help him to understand that physical revenge is not an appropriate response as it is likely that he will get in trouble, as well. For more ideas, on helping your son manage the teasing, take a look at the following section of this website:

http://www.education.com/reference/topic/TeenYears_MiddleYears_Bullying/

Good luck!

L. Compian, Ph.D.
Education.com Team