No one should ever not feel safe. It is our jobs as adults to provide and environment where growth can occur. My son is also on of the odds ones who pokes and such to get attention. Some of it is normal behaviors for learning boundries, but what is happening to your son goes beyond. Let the teacher work on it for a while and see what happens. She will be watching for behaviors by all the boys, so be prepared to find out what yours is doing too.