Cats talk with their tails, ears and body language. If their ears are back, it means they are getting angry or frustrated. Their tails will stand straight up, which means "notice me", but down or tucked means "I am afraid but ready to fight if needed". Their body language is easy, if they are laying near you, then they are comfortable with you and you can pet them. Try to pay attention when your cat slaps you with their paw or cries out and turns to the area you are touching. This means either "I have had enough petting for now" or "I hurt there so don't touch". If your cat lays by you and seems to be okay, but snaps or swats you when you pet him, get him to a vet because something is probably wrong. I hope this helps, Cheryl.