What is the origin of the idiom "be in clover" and when to use it?

The idiom "be in clover" has its roots in rural traditions, particularly in agriculture. Clover is a plant that is commonly used as fodder for livestock. Livestock that grazed in clover fields were considered to be well-fed and content. This phrase is used to describe someone who is living in a state of luxury, comfort, or great prosperity.