Definition & Meaning of "[turn] on the waterworks"

What is the origin of the idiom "turn on the waterworks" and when to use it?

The idiom "turn on the waterworks" originated from the theatrical practice of using waterworks, such as hidden pipes or mechanisms, to create the illusion of tears during emotional scenes on stage. In the early 19th century, before the invention of special effects or artificial tears, actors would activate these waterworks to produce a flow of tears, enhancing the dramatic impact of their performances. Over time, the phrase "turn on the waterworks" became a figurative expression, referring to someone deliberately and ostentatiously shedding tears or displaying exaggerated sadness or grief.