Yep lofting is fluffing it up so fluff the end that is overly stuffed and quickly compress that compartment whilst trying to suck it into the other compartment by trying to expand the walls.

Down will rot, its natural after all, just depends on how damp you get it for how long. Down for me usually looses loft underneath (not that that really matters) at the head and foot as it rubs on the walls of the tent and round the mouth due to moisture in the breath. Its probalbly unlikely to be mid way down the top of the bag. There is probably a moisture level it rots at like wood, which is usually about 20 percent water at any one time, yet does not rot. Down will loose its lofting capabilities though, its why storage is reccommended decomressed.