"The lavatory is inlaid with gold" is a metaphor, which is used to describe that in bad things or negative situations, some ostentatious or superficial things are decorated, pretending to be magnificent or beautiful. This sentence is also called "urine jar with gold edge", which means "mouth" is good. Urine jar and lavatory are mostly made of mud. If it is inlaid with gold edge, the mouth will be fine. Mouth, mouth also. Metaphor is that people have a good mouth (but people are not very good); Or a metaphor for someone who can speak.