Once you have washed your goose down sleeping bag to remove any dirt or dust that might have gathered on it during camping or a sleepover, it is time to dry it, so begin by wringing any excess water out of the sleeping bag that might have been left in post-washing. After this is done, proceed to prepare your dryer.
Set the dryer on the lowest heat setting, and if your dryer has an option for no heat setting at all, set it to this. Then, put your goose down sleeping bag into the dryer, and press the start button to get the dryer going.
While the sleeping bag is drying, do not leave it alone, Keep checking on it regularly, and make sure the exterior does not overheat during the drying process. As it dries, clumps of insulation will form in the bag, so remove it from the dryer after every hour or so, and break up these clumps. Then, return the bag to the dryer, and start it up again.
The bag will take a long time to dry (a couple of hours, at least), so be prepared for that. When it is almost dry, toss a few tennis balls into the dryer, as these will help break up the insulation entirely. Once the bag is dried through, you may remove it from the dryer. Store as you normally do.