I use magnets. What you do is glue two or three strong magnets to the inside of the bio, right in the middle of the forehead. Then you glue another two or three strong magnets on the inside of the mask, at the same place on the forehead (glue around the edges of the magnets--you don't want anything in between the magnet and the mask). Then, when you put the bio on over the mask, the magnets should line up and lock together, holding the bio in place. And since the magnets are on the inside of the mask, you can't see them when you take the bio off.