It is fully adjustable, so you can have it tight, loose or only fixed on one side etc.
You will need some trouser waist band elastic (like in kids trousers). I made some tabs to go on either end of the elastic before gluing to the mat (with two part glue). You could sew them to the mat.
I have 3 strips of elastic that correspond with the loops on the quilt.
My quilt has 6 sewn in loops to which i tied a loop with a "toggle".
The toggles go through the elastic obviously, and are easily adjusted whilst on the mat/ under the quilt.
Oh and the elastic obviously has plenty of give so there shouldnt be any stress to the quilt.
The cans are holding the elastic down whilst gluing in the first pic
