Definition & Meaning of "[be] sitting pretty"

What is the origin of the idiom "be sitting pretty" and when to use it?

The phrase "be sitting pretty" is thought to have originated in the 19th century. It is believed to be a reference to the fact that people who are sitting in a comfortable position are not in danger of falling over. In this sense, the phrase means that someone is in a safe and secure position. The word "pretty" in this phrase is used in the sense of "attractive" or "pleasing." This is because people who are sitting in a comfortable position are often seen as being relaxed and content. In this sense, the phrase means that someone is in a good position, both physically and emotionally.