Ah, here I go again. I said I wouldn't give any writing advice but I have something else I wanted to say about it. Forgive me. It's not that I think I really know how to write. I just tend to do it, on occasion.
What I take Hemingway's phrase to mean is this. When I'm writing, I try to go for that level of elation you might have when you have been hitting the bottle. Whether you have a social drink now and again or not is likely irrelevant. Even a tea-totaler will get what I'm saying here. You remember those times, I'm sure. Your inhibitions are weakened. You might go and ask someone to dance--even if you never do that. Or, you might share an opinion you know won't be popular. Maybe, here's hoping, you'll try something you've never tried before.
The metaphor is the same when telling your story in novel form. Do all those things when you're writing a scene...or a whole book. Try stuff. Let the cautious 'you' take a holiday. Write like you're drunk. And worry about the editing in the morning.