That colorful expression by the late Lewis Grizzard can be roughly translated as, "Don't tell me about my business." Which is exactly what's wrong with Rod Dreher presuming to criticize Mark Levin:

Most people never really think about the craft of talk radio, just like they never think about the craft of journalism, or the craft of blogging, for that matter. . . .
There is something that Moe Lane calls blog fu, and until you get a million hits, I don't want to hear you lecturing me about blogging, OK? Ditto anybody who wants to lecture Rush Limbaugh about talk radio.
Because Rush is the very best at what he does -- nobody in the talk-radio industry even questions Rush's absolute supremacy -- he makes it seem easy. It's just like you may not think much of a particular Bad Company song, but until you get up in front of a crowd at karaoke night and actually try to sing "Can't Get Enough," you don't realize what an extraordinary vocalist Paul Rodgers really is.
This is what's wrong with Rod Dreher and Conor Friedersdorf criticizing Mark Levin: They are not qualified to do so. . . .
Levin must compete in the radio market. It is that simple. . . .