Tail wag.
Meaning: This means for a dog to move its tail back and forth quickly. It's like saying, The dog is happy and showing it by moving its tail.
Choice of Words: Tail is the long, thin appendage at the hind end of an animal's body. Wag is a verb that means to move back and forth rapidly. When you put them together, "Tail wag" means for a dog to move its tail back and forth rapidly.
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