I use Peltex which is an ultra, super stiff fusible interfacing. You can buy it at JoAnn's. I cut 2 pieces to the size I need and iron or fuse them together. It's then very stiff after it cools from the iron. Next, I sew it to re-enforce it in small triangles starting at one end of my piece sewing up on an angle and when you get to the end, you pivot the fabric and go back down to finish up the triangle. I try to get 3 or 4 triangles across my piece. Once again, doing the stitching re-enforces the Peltex. Then depending on the purse I'm making, I try to sew it directly into the "inside" (beteen the layers of fabric and the batting) of the bottom of the purse and then sew it down around the edges of the bottom of the bag as opposed to "sleeving it". The sleeves work, but as someone else mentioned, they do shift around in your bag a lot and stuff does in deed fall underneath. But my long arm quilting lady told me about this and it works beautifully. Only one problem, peltex is not cheap, but best to buy it at Joann's when they either run their 50% off on interfacings, or those of you who were lucky enough to get the 60% off coupons could stock up on it if you make a lot of purses.