Sounds very random I know, and it is! My cat is long haired and has recently started to get sudden twitches down his back, then licks those areas very aggressively repeatedly. He'll stop doing it for a while, then just when I think whatever is is has gone, he does it again! I've treated him AND my house for fleas and he has just had the second application on his neck, but he is still doing it. It's not a constant thing, just every now and again......has he gone mad?!