A few minutes ago I read a writer’s blog and in it the writer took offence at the above quote stating that this quote was erroneously attributed to Hemingway. (Your guess is as good as mine.)
Second, the blogger said that Hemingway didn’t write while drunk. He wrote in the mornings before he drank. (Again, who knows.)
“Get a Grip!” It’s tongue in cheek. And it’s funny.
The point is: Write when you are uninhabited, when you are loose, free, and willing to put anything down on paper. Then when you are clear headed go back and edit. This is sage advice.