I tried dampening by using iron on steam with steam-push button
It occurred to me maybe it is because I starched it first.
Dampening and steam helped but it still peels right off as soon as I pick it up. The pressure of the stiff batting is more than the adhesive glomming it to the fabric can take.
I am trying another fabric which hasn't been touched by magic sizing, but it doesn't seem to make a difference
Thanks for your suggestion - I'll keep trying.