I've never had a problem with him thumb sucking but recently he's being teased in school, and his teacher has made comments on more than one occasion that we should be encouraging him to stop so...
The last week when he's asleep I've been paining his thumb mails with the nail bite stuff, I have said nothing to him, made no big deal of it, just watched. He's not been distressed by it at all. Today very matter of factly he said 'Mummy I think I must be getting too grown up for thumby cause it tastes funny now!'. Very funny..
I think he's coped really well. (DH thinks I'm being cruel!)
Thought it might be usefull to hear how anyone else has cracked it.. and thought somebody else would find this useful!