if you don't have any wash-away stabilizer handy, try the same technique using fine mesh tulle...it will stay in, obviously, but in the stitching it will create it's own texture as it sometimes bunches and scrunches with the tension of the threads, etc....and because it does stay in it's possible to use smaller pieces of scraps.
If you're careful, and at the end of the process, insert non-sewable small materials (like charms, sequins, etc) under the top layer of tulle then carefully stitch around it making a closed pocket so the item stays in place