What is the origin of the idiom "keep one's shirt on" and when to use it?

The exact origin of the idiom "keep one's shirt on" is uncertain, but it is believed to have emerged in the early 20th century. This phrase may have originated from the idea of keeping one's shirt on as a symbol of self-restraint or keeping calm. It is often employed during moments of frustration, conflict, or impatience and can be utilized in personal or professional settings, such as in arguments, heated discussions, or situations where emotions may run high.