What is the origin of the idiom "the fat is in the fire" and when to use it?

The idiom "the fat is in the fire" has its roots in the practice of cooking, specifically when excess fat or grease accidentally catches fire. This situation was often dangerous and difficult to control. Figuratively, the idiom means that a difficult or dangerous situation has occurred, and there is no turning back or avoiding the consequences. It implies that the situation has escalated to a critical point where immediate action or resolution is required.