probably just fluff it up like a down pillow.. is my guess i dont have much experience in this department
is it lumpy or all over flat? new or used? My coat, the only one I've ever bought new, is showing some age and slated for cleaning this spring (that's about June) I have tossed it on air fluff with my chacos (sandals) as fluffers. is your down actual down of synthetic? they are so good these days that I would ALMOST switch.
I bought a down comforter and it arrived flat, they said to lay it out for a couple of days and it would be fluffy and i did and it did so all was well in the house of the new down comforter!