[header] How to help a reactive dog relax around food [title] Get to know your reactive dog's body language. [step] The body language of a reactive dog can be difficult to discern. But generally, a happy dog will wag its tail, perk up its ears, and raise its head. 
An agitated or aggressive dog will growl, stand stiffly, snarl, snap or bite, and lower its head to line up with its spine. Watch your dog's head, tail, and mouth closely for signs that indicate its mood.