This will work with any hammock that has a zipper for a detachable bug net or cover. In my case it was an Warbonnet Outdoors XLC.
The problem: Underquilts popping off the outside (head side) shoulder.
Solution: Use a Dutchwaregear.com quilt hook and pack hook to create a movable, removable, attachment point for shock cord. The pack hook is connected to the quilt hook and the quilt hook clipped over the zipper on the edge of the hammock. The quilt hook holds firmly over the zipper and does not move easily. The position allows one, on the XLC, to close the bug net or top cover completely locking the position of the quilt hook and pack hook.
In the case of the XLC, the quilt hook clips on nicely right at the end of the zipper run near the head. This has, for me, eliminated any chance of an underquilt popping off the shoulder in the middle of the night.
This approach has worked well for me using an Underground Quilts Zeppelin and an ArrowHead Equipment Jarbidge.
The quilt hook did not stay in place on a standard hammock edge, i.e. no zipper.