I think this problem must stop children, and don't think that children will be fine when they are old. I think this view is wrong. Because it is a matter of habit. First of all, you should enlighten the children, of course, not strictly. You should let him know that this is a very bad and unhealthy habit, and tell him that if other children see this, they will be ashamed. If he talks too much and is embarrassed to touch it, he can't control it every time. You adults should stop it in time. After a period of time, he will know that this is a bad habit, and he will not touch it again. Believe me, I am an educator, and this kind of thing often happens to me. I have used that method many times and the effect is very good. I hope your child will get rid of this bad habit as soon as possible. At the same time, I wish your children healthy and happy growth.