Thumb Sucking

[CeciC]

I hope I can get some advice on how to stop my DD2 5 year old sucking her thumb. Usually she just does it when she is tired, but her teeth are out of place. Her oldest sister has a retainer as she used to suck a dummy.
I have tried cover the thumb with plasters but usuallly the are out later in the night.
Any advice welcome

No ideas but interested to hear what others sugguest. DD1 is on same path.

My 5yr old DD2 is a constant thumb sucker although her teacher says she doesn't do it at school. Don't actually believe her though!

There is a product called Thumb guard here which looks good but i can't afford it. There is also someone on Ebay here makes thumb guards but they need to be worn 24 hrs a day for around 3 weeks which would be tricky with school. Thinking about getting 2 for use during the summer hols of she is still as bad.