Kate, pick your mind back up out of the gutter! I meant points in the writing when you stick tighter than a plump gent superglued onto a toilet seat. The point at which writing at all seems futile, and what you've already done feels like a waste of effort. I have two or three of these every book, minimum.
So: how do I get away from it?
I can't afford to simply drop the book and write something else - until I reach the same point, yet again. (there are people out there who do this. Who have hard-drives full of great starts...)
It's usually my subconcious telling me that something is badly wrong. Of course sometimes my subconcious is talking a crock and should crawl back under its rock and stay there, but mostly it's saying 'something ain't right and ain't fair. According to the Goons - I was writing the left leg of Joe Louis ;-) -- but in practice for me it usually means motive is insufficient for prescribed course of action of the plot. I have 3 solutions - all working round that.
1)Go back. Elaborate on motive.
2) Add a new POV character - who will expand that motive
3) Jump ahead. Just leave it right there, and jump ahead - This is great when you really aren't yet sure what motives are -- they'll reveal themselves and you can backfill.
So I am still as sick as a... why the hell horse? A hippopotamus with double pneumonia -- so I'll leave you to tell me what you find works to deal with the sticking points.