If your dog has chest congestion that is making breathing difficult, the vet may try coupage, a way of loosening the phlegm in the airways by gently tapping the dog's chest. Then your dog can clear it more easily.
Coupage literally means "cutting" in French. When a veterinarian performs coupage, he or she is attempting to loosen, or cut through, the congestion, which might be caused by pneumonia or bronchitis. Another sense of coupage is in the world of winemaking. After the initial fermentation process, different wines may be blended together in order to combine the best qualities of each. Adding something to a substance in this way is often called "cutting." Coupage sometimes refers to a similar process of blending in the production of gourmet cooking oils.