Writer's Laziness
Similar to Writer's Block, Writer's Laziness is when you can't write, but for a different reason. You know exactly what to write, but are just too lazy to type anything up. Currently, no exact cures have been found. It is commonly associated with procrastination and may be remedied by an impending deadline, but data is too scattered to make a direct correlation.
"When is the next chapter of your book coming out?" "I know what to do, but I have Writer's Laziness."