My couette is thinner, how can I make a contribution volume to the feathers again? Couple of years ago my couette (aka bed duvet) was 4 inch...

Couple of years ago my couette (aka bed duvet) was 4 inch tacky giving a wonderfull cover for winter nights

But in a minute its flattened, maybe 1-2 inches gooey, feathers seem smaller amount fluffy

Anyone has a recipe to catch the feathers fluffy with more volume again? Is it unmoving? Should i shake it vigorously? Or does this involve profesionnal care?
How to verbs a suede Jacket!?
Answers:    Wash within large front loading contrivance on warm, and dry contained by a large dryer, near a pair of verbs sneakers. Dry 'til completely dry. 40-80 minutes.