You shoudl NOT NOT NOT attempt this unless you have been trained by an Occupational Therapist (OT). Period. If you don't do it the right way, or brush certain areas you shouldn't, you cause MAJOR problems. Just ONE example is if you brush the abdomen you completely disrupt digestion in a way that is very painful. There are other pitfalls also.
The Occupational Therapist (OT) will have the brush. Our evaluation, a few years ago, was covered by our insurance. The school Occupational Therapist (OT) should be able to show you the technique also, though they do not do it at school usually and they do NOT do a complete assessment - they just look for ways academics are affected.
AFTER you have been properly trained you can buy the brushes at Occupational Therapist (OT) supply places like
www.southpawenterprises.com.
You do your child NO favors by teaching this to yourself. There are also gentle joint compressions that come after the brushing. Done wrong they can also hurt your child.