What is the origin of the idiom "have someone over a barrel" and when to use it?

The origin of the idiom "have someone over a barrel" likely stems from literal scenarios involving physical restraint or vulnerability. It is related to the practice of punishing or disciplining individuals by placing them over a barrel, where they would be physically immobilized and unable to escape or resist. Another potential origin comes from the concept of barrel usage in the shipping industry. In the past, when a person was trapped inside a barrel, they would be at the mercy of those in control, as their movements would be severely restricted.