In the line from the excerpt below, which part is a metaphor?
**The large woman simply turned around and kicked him right square in his blue-jeaned sitter.**
his blue-jeaned sitter?
kick him right square?
The large woman?
His "sitter" is what he sits on. That's the euphemism for his rear end/buttocks/bottom/ass, depending on your normal word. I don't see it as much of a metaphor, though.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.