Usually, when clothing is tight, it's a bad thing. Not so if you're an anxious dog! These snug-fitting jackets that have helped countless dogs suffering from noise phobia, fear of thunderstorms, and all kinds of other anxieties. For decades, trainers have been recommending these wonder-garments. How do they work? No one really knows, but they do! Trainers often equate it to what a baby must feel when swaddled.