A dog in an offensive threat posture has its tail up and stiff,
its hackles up, its ears forward, and stands tall and forward on its toes. It may be barking and growling and holding direct eye contact with other dogs, and it will more than likely attack at the slightest provocation.
Playful barking, on the other hand, is more likely to happen when the dog demonstrates a play bow, showing that he wants to play with a person or another dog. His tail is up and wagging, his ears are up, his front end is lowered, and his mouth is open with the tongue visible. If greeting another dog that is not showing offensive, defensive, submissive, or stressed body language, the owners can supervise and allow the dogs to play.