What is the origin of the idiom "like a dog with two tails" and when to use it?

The origin of the idiom "like a dog with two tails" is not definitively known, but it is believed to have originated in the United Kingdom. The expression likely emerged from the observation of a dog wagging its tail vigorously, which is a sign of excitement and happiness. The phrase is used in a variety of contexts, such as sharing good news, expressing enthusiasm about an accomplishment, or describing someone's ecstatic reaction to a pleasant event. It can also be used humorously to convey a playful exaggeration of happiness.