Unfortunately I am in the same exact boat! the speech pathologist told me to get some gauze and pull on it a few times a day to stretch it. It seemed to help a bit, but it would only be able to stick out a tiny bit further temporarily, and the next day it would seem to shrink back. I stopped doing it because it was starting to irritate my tongue, but I might try again. My real tongue will stretch, its the flap that has no give.