7year old sucking/chewing clothes.

[imayhavelostmymarbles]

My DS used to chew/ suck collars and sleeves as a toddler, and has started again in the last year or so-or it has become more obvious.
Chewed a hole in his new coat collar that he's only had 2 weeks.
He does it absent-mindedly so although I have reminded him, and tried consequences he just doesn't stop. No SEN and he tells me nothing is making him worried although he is quite sensitive. What do I do? Help!

My dd is 7 and does the same and with teddies too (it stinks) - I think it's a comfort thing like sucking a thumb but it destroys otherwise nice tops. No idea how to stop it. I assumed she'd grow out of it when her peers start to notice