"[go] down the [tube]" 的定义和意义

What is the origin of the idiom "go down the tube" and when to use it?

The idiom “go down the tube” is believed to have originated in the 1930s, when people would throw unwanted items down the sewer pipes. Over time, the phrase came to be used in a figurative sense to describe anything that is going to waste or being ruined.