Tail wagging is one of the most recognizable non vocal communications, but the manner in which the tail is carried also indicates the emotional state of dogs. A tail carried at a jaunty angle, or wagging slightly like a waving flag is sure sign of contentment. A lowered tail that is tucked between the rear legs is a certain signal that the dog is either in the immediate presence of what is considers a dominant creature, or is cowering in wary expectation of punishment. Even those schnauzers whose tails have been surgically docked can convey their emotions by the way they wag their abbreviated tails. some dogs will actually smile by drawing back their lips as they wag their tails with exuberance; others smile with their tails alone.
How he carries his ears also conveys non vocal messages of how a dog feels at any given moment though, in a schnauzer with cropped ears, the ear flaps are much less mobile than those of an individual with natural, uncropped ears. Schnauzers tend to carry their ears erect with only the outer 1/3 bent forward by their own weight. When unhappy, they drop to the sides of the head.
When agitated, the hair on the back stands erect.
And when he's happy, he often dances about on his feet, especially his front feet, in a disply of bliss at being noticed.