Well, it seems the internet has provided context as useful as a chocolate teapot for your specific problem. Instead of helpful hints, we've got YouTube's legal boilerplate, which won't fluff anything but a lawyer's feathers. So, let's ignore that and get straight to reviving your sad, pancaked cushions.
First, embrace your inner aggressor. The easiest and most satisfying method is a good old-fashioned beating. Take the cushions outside, unless you fancy a home filled with floating fluff, and give them a thorough thumping on all sides. Punch, knead, and karate-chop them with gusto. You want to break up the clumps of down and reintroduce air into the filling. Think of it as tough love for your furniture.
For a more advanced technique, if the cushion covers are removable and the care tag doesn't forbid it, you can turn to your dryer. Place the down insert into a large commercial or home dryer on a low-heat or no-heat air-fluff setting. To really get things moving, toss in a few clean tennis balls or wool dryer balls. These act as tiny, relentless pugilists, pummelling the feathers back into a state of plump perfection.
Finally, a bit of sunshine can work wonders. On a dry, breezy day, lay the cushions outside for a few hours. The sun helps evaporate any moisture that might be weighing the down down, and the fresh air helps restore its loft. It's basically a spa day for your sofa, and soon enough, it will be back to the cloud-like throne it was always meant to be.
