I sucked my thumb when younger, although my mum said that even as a teenager I would sometime suck my thumb in my sleep or when really tired. My mum tried everything but I think the main thing that stopped me was getting braces.

I tried everything with my daughter. She used to pull her shirt up and wrap it around her hand while she sucked her thumb and pick at the hem with the other hand holding the shirt and her thumb. Her thumb was bigger from the sucking too. In the end she grew out of it when she started school

Put something that tastes yuck on her thumb during the night

I was a thumb sucker until I was 12, my mum tried everything but nothing worked and if anything, it made it worse because I knew it was ‘bad’ but I couldn’t help it. I was an anxious child so it was a comfort thing for me and I honestly just grew out of it. If your little one is an anxious child, maybe research ways to help with the anxiety and behaviour regulation and the thumb sucking may just stop on its own.