Why does the quilt core always move down when sleeping, and there are always extra parts on the quilt?

It should be where the quilt is empty. Adults' sleep habits will lead to the core moving down. In this case, you must fix the quilt core. The simple method is to simply sew the quilt cover on the four corners with needle and thread, because people's movements will not be so exaggerated, so they will not move the quilt core in the quilt cover.