I don't think there is such a thing. If I feel stuck, I simply get up and move to a different spot. More often than not, as soon as I close my computer, the words start flowing again. The biggest thing is to get away from a blank screen. Vacuum. Go for a walk. Talk the story out. Talking is really useful. I have a voice recorder I carry around so I don't forget anything. For years I wrote in cafes and coffee shops, (very cliche) but I'm addicted to TV so I couldn't work at home. So, I bought a lot of chai lattes as I moved from shop to shop. Now, I live in the remote woods so no more coffee shops and cafes. When I get stuck, I walk the dog and talk the story out to her. She's a very good listener. Unless there's a chipmunk nearby.