My nephew is a BIG time shirt chewer. I noticed that he isn't even aware that he is chewing. I thought that if we could do something that would help him to become aware of it at the time that he is chewing, it might help. The idea to put duct tape on the neck line came to me. It seemed to work. As soon as he felt and tasted the duct tape, the shirt came out of his mouth.
If sees that the majority of shirt chewers in my family are boys...hmm...
