Essentially a duvet is a very large quilt of some kind that is filled with an extremely puffy inner filling such as down or cotton, and this is usually used in place of items like a sheet or an upper blanket.
If you have a dream in which you are using a duvet then this means that you are going through a very sensitive time in your life right now. You feel like you really need that extra level of comfort in your life to feel regular again. This is what the duvet is all about, to make you feel more comfortable, less sensitive. If you have a dream where a duvet takes the main stage then this means that you are going to have to do a lot of work to make sure that you don't appear too sensitive on the outside as well. Sometimes you can be a little too oversensitive and it will cause you to appear weak.
If you are in a position of power or if you are trying to earn respect, being sensitive and bursting into tears won't do it for you, it will only make you look more foolish and less like leadership material. The duvet is known for being made of only the highest quality and most comfortable materials. If you have a dream that you are using one it can only mean good things for you. You should pamper yourself soon, you deserve it.
A duvet could simply be a sign of luxury. Perhaps you are living the good life for one night or perhaps you have recently decided to be a more pampered person. This means that you will be able to do much better in life later on.