When a child has oral sensory issues it can cause a lot of problems. Our biggest one with our son happened to be he was chewing on his t-shirt collars so bad they were stretched and beyond repair. Besides that once they were chewed they got wet and he'd take it iff and refuse to put it on again because it was wet.
Here is a picture of ours. I did find at Sports Authority they have colorful rubber tubing of different strengths and thinknesses.