My 4 year old exposes himself

[MY4YROLD]

Recently my 4yr old has been exposing himself at school. My husband and I have spoken to him about private parts and good and bad touches,that its part of the rules that you don't show your privates,just like no hitting or calling names at home and school. It seems to be getting worse.  I got a call from the teacher that my son and a couple of the other boys in class were caught touching each others privates while having free time on the playground, then the next day he touched one of the boys bottoms while in the bathroom. Now he unbottoned his shirt and pulled down his pants and I found out that he was trying to pee in one of the kids mouths...Now we have gone as far as keeping him home from school because we told him that if he continued he wouldn't be able to go to school anymore,I took him to the library and read him books and showed him pictures asking him if he understands and has any questions. He seems to understand what he's doing is wrong and he doesn't have any reason for his behavior. I'm not concerned that he has been abused in anyway,but I just don't understand why he keeps doing this even when he knows its wrong and gets punished. What can I do to get this to stop? Should I get him counseling?    

[margypops]

Sounds like he has learned this behavior it is doubtful he started to do it  spontaneuosly  is he around any older children babysitters?  family members.possibly even from one of the boys at school as he wasnt the only one, did the teacher call the parents of the other boys.You say he keeps doing this how many times and has he done it at home?