Wash your cotton-filled comforter according to care instructions. Set your dryer to a low heat setting, and place the comforter in it. Add three tennis balls. The tennis balls move against the comforter during the drying process, punching bunches out.
Spread the comforter out on your bed. Stand at the foot-board of your bed, holding the bottom of the comforter. Bring the comforter edge up to eye level and pull it down to the bed in a fast motion to disperse bunches. Repeat the process until the cotton filler evens out. Fluff your comforter daily.
Feel for bunches of filler with your hands. Move your palms or elbows outward over clumps to smooth it out for an even layer of filler.
Flip your comforter to the other side. Rotate it weekly to even out the cotton filling and wear of each side.