We bought this thumb guard to help our son. http://www.amazon.com/Stop-Thumb-Sucking-Thumbusters-Pink... We tried the hard plastic kind, but htey looked like midevil torture devices and he couldn't sleep because he was uncomfortable. He could stretch the softer guard to get his thumb out, so we gave him incentive to keep it on. We told him that once he didn't need the guard any more we would buy him a set of the little legos (he had been wanting to move up from the Duplo legos :) ). The first week or so he took it off a lot. We didn't chastise or anything. We told him we knew it was a really hard habit to break, but the habit was hurting his teeth. And of course we mentioned the legos. After that first week we noticed he wasn't taking the guard off any more. So we took the guard off after 10 days and he had stopped. My BIL is our dentist. ANother trick of the trade he mentioned was putting an Ace bandage just on the elbow. It makes it uncomfortable when they try to bend their elbow to suck their thumb. Our son wore it happily, but would rip it off in his sleep no matter how we secured it, so that one didn't help us. We also tried a band aide on the thumb. My son would complain that it made his thumb sweaty and always tore it off. The thumb guard worked great, It comes in a bunch of colors, so we let him choose what color he wanted.