What is the origin of the idiom "wet blanket" and when to use it?

The idiom "wet blanket" originated from the literal concept of a wet blanket, which is a damp cloth that, when placed on something, extinguishes or dampens its fire. The idiom figuratively refers to a person who discourages or dampens the enthusiasm, excitement, or enjoyment of others. It suggests that the person's presence or actions dampen the spirits or excitement of those around them, much like a wet blanket dampens a fire.