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Cats often itch as part of their normal grooming routine. But if it has flies, it can happen more frequently. You may be scratching some part of his body (probably the hind legs or the base of the tail), and he may start chewing with his teeth to soothe that area.If your cat has a flash, you will see him lick more. Like the extra itching and chewing, the extra grooming tries to relieve itself and get rid of the flashes of his coat. He can even do it very well, since all this licking can actually make it hard to see fleas on his fur.This search may result in scratching, chewing, and licking some parts of your cat.