Someone will post a link to that Youtube clip soon where they show you how to put on a duvet cover by rolling up the duvet first.
I never understood it, but those who do say it's brilliant, no effort, and much quicker.
I always wash the duvet cover inside out, put my hands in and grab the corners of the duvet and then shake it over the banisters so that the cover drops down in position. It's a bit of an effort in winter with the heavier duvet, but basically it's easy that way.
Most new washing machines these days take a larger load, so with one of those you can wash your own duvets.