My son is 5 years old now. I am a little disturbed to hear from his class teacher that he has been masturbating in class during free time. She has seen him to do it a number of times. When caught he covers up immediately but is not able to stop himself from repeating the activity again. I had talk with him and he confessed that he does it since it feels "really good" and told him to do it in complete privacy of his room or the bathroom. He agreed but last week again the class teacher came up with the same complaint. He studies in a co-ed school and his teacher told me that a few students including female students know what he is up to and always try to be around him when he is doing the act. He gets embarrassed and stops when he sees other students watching him but starts again when he thinks he is not being noticed. I am feeling quite stressed, as to how to approach him on this matter?