This is actually something I used to do as a child... I outgrew it eventually but I always remember my mom being so upset about the clothes I ruined... to this day I tend to chew on my pens when I am working... I will say this, I am an extremely successful adult,I have no idea why I did it, I just always thought of it as a bad habit. I do love chewing gum as well and chew at least a few pieces a day... I agree with Special mom that is most likely a way to calm him self. I do remember just about every shirt I had, had a small spot with tiny holes it it :)...
Hello. This is usually a sign of anxiety and this is a self soothing technique. My son has sensory integration problems and self soothes this way. One thing to try is to offer alternatives. Therapy websites sell different kinds of things to offer--- a hard rubber p or t which are smooth or textured. They sell various toys that are for this purpose, some vibrate. You could tie a bit of tubing around his wrist or make a necklace. You could put some beads on a string for him to wear. When he is a bit older--------- at school they will give a child a coffee stirrer to chew on or a cut straw. They also make tips for the tops of pencils/pens. I would not really try to stop it as he is trying to feel better and calm himself. Figuring out what the underlying thing is that is driving it would be helpful. Give him something chewy like fruit chews, bubble gum, fruit roll up, or licorice before going somewhere.
good luck. (never punish for this-------- your child is calming/coping.)
Oddly enough, I know a boy in my family that did that till age six... he still might be. He'd chew holes in his sleeves. I'm not sure why they do it, but it may just be a form of hyperactivity where he has an urge to chew on something; though, that's just an assumption. That's also not saying he's got Hyperactivity Disorder... children aren't going to be calm like an adult anyhow. lol