This cat most likely has fleas, or a skin disease, or both. My cat never did this, and then one day we realized she had a lot of fleas. The vet said she was allergic to the fleas and caused her skin to become flakey like dandruff, and sensitive. When you pet her hindquarters, she did the same exact thing as in this video. After a flea shampoo treatment and carpet treatment, her skin became normal and she no longer exhibits this weird behavior. Please take your cat to a vet and have him/her checked out.