Not writing "drafts" doesn't mean that whatever you write down the first time is sacrosanct. Did you ever ask a student to revise a paper and you get only a few changes, the exact ones you have suggested? That is not what I mean at all. Every time I look at something I've written, before it is published, I make some changes to improve it.
Rather, that the prose you write is basically fine the first time around. It doesn't aim for shittiness or roughness but for smoothness.