The simple rules of using a comma before and after the vocative case state that you write, for example, What do you, Mark, think about the book?
But what about “you guys” / “you, guys”? Or, for that matter, “you Mark”?
Are there instances where it would be correct to use a comma and instances where it can be omitted, thus altering the meaning of such a sentence?
What happens to sentences like Where are you guys?