The ears stay forward. Tails are wiggling. There's no growling or hissing. Biting is not accompanied by punching with the feet. Bites don't draw blood.
Slaps are gentle and usually with only one or two paws.
Never reach into a cat fight or hit a cat. Either behavior can make the animals more aggressive and you risk becoming one of the wounded. If you did, please send an e-mail to let us know.