To code quickly you should just code quickly. To code difficult stuff lying on the sofa or talking a walk is an excellent way to "meditate" on a solution. If you think through a problem that way the ensuing coding will be quicker and better and save you some trial and error.

It's too bad that most workplaces arent conducive to that kind of workprocess (try lying in a sofa at work and not be called a slacker :)