One is being faced with a tangle of wool. You find a loose end, then you tease all the knots out. Sometimes the text will fall happily into orderly loops with merely a tug or two; sometimes it will be a fight for every clear inch.
One other is almost more a physical feeling than a description. It's that feeling you get when you gather up a duvet and, with a deft flick of your wrist, roll it out over the bed and watch all the creases magically disappear. Disorder is transformed into a smooth expanse.
I like to ask other people what their metaphors are, and I like it when I stumble across people's metaphors, as I did this morning with Barbara Epler:
Actual editing consists so much of petting and patting beautiful writing.
With the poets, that means allowing for differences. One poet, alive like the inside of a light bulb, requires five or six sets of proofs: allow time. One might need a suggested re-jigging of the order of contents: allow possible irritation. Allow "grey" and "gray" in the same volume (the former greenish and the latter more blue: the opposite of what I'd guessed).