When refering to getting a lot of work done fast, would the correct saying be "...flush it out...", or "...flesh it out..", anyone?
I haven't heard either of those quotes said in relation to a lot of work done fast.
IMHO 'flush it out' would mean removing a blockage by forcing air/water through or bringing something out into the open, and 'flesh it out' would mean buiding it up, making more of it, making something bigger.
Unless some more learned Aber (of which there are many!) can shed better light on the matter, to me, they mean very different things.
I wonder whether it might be 'flash' rather than 'flush' or 'flesh'. I've never actually heard the phrase 'flash it out' used to mean get something done quickly, but 'flash' does give a suggestion of speed, as in "I'll get that done in a flash."
I tend to think rcjw has heard 'flesh it out' and has misunderstood the meaning.
Imagine writing a story, and starting with a skeleton:
Woman walks along street
Three buses pass without stopping
Woman walks into bar to call a taxi
etc.
After fleshing it out, it might start 'The young woman looked very attractive as she walked along the main street of the small market town'.