It is slow for a new sleeping bag to fluff up since it has been jammed in the compression bag after leaving from factory. There are some tips to help your down sleeping bag fluff up faster.
1. After pitching camp, it is advisable to spread your sleeping bag a few hours before bedtime so that the down is fully lofted (if the campsite is very humid, keep your sleeping bag dry is the whole of all thing).
2. Lift the left and right sides of your sleeping bag and shake a few times to make the down evenly distributed in its lining.
3. Then gently pat the sleeping bag from head to toe, with a very light force on the line, in order to make the down evenly distributed as fast as possible.
4. Make sure there is more room for expansion of down
5. Lay it flat on and leave it fluff up in tent.