DS doesn't have a dummy as he was breastfed and had me as a dummy. However he has his "doo doo" which is an old shirt of mine that he chews on vigorously when he goes to bed. He doesn't just suck on it like most kids, there are hundreds of tiny holes in the shirt of where he has put his teeth through.
This is the one behaviour that worries me the most. The licking and chewing of very inappropriate items. Hairbrush isn't that bad. Try the toilet freshener that hangs in the bowl