1. Turn the cover inside out.
2. Stick your hands into the far end corners of the cover
3. Grab the corresponding corners of the quilt
4. Holding both the corners of the quilt through the cover, slide the cover as far as possible over the quilt
5. Let go of those two corners
6. Put the two remaining quilt corners into the cover corners near the hole, quilt is now entirely in cover
7. Grab the two corners you did last (near the opening)
8. Flap around quilt+cover violently
Hey presto