What is the origin of the idiom "in hog heaven" and when to use it?

The origin of "in hog heaven" is uncertain, but it likely stems from the association of hogs or pigs with indulgence and pleasure. Pigs' reputation for enjoying food and their voracious appetites may have inspired the idea that being in "hog heaven" means experiencing extreme happiness and contentment, akin to a pig's delight when provided with ample food or a favorable setting. It can be used to express a sense of ultimate happiness and contentment, suggesting that one is in a state of bliss or heaven-like pleasure.