Mod Podge is NON-FLAMMABLE (use on the outside of a lampshade). So don't worry about the bulb. . . you are good to go.
Here's how to do a project such as this. First of all, you'll need enough fabric to cover the shade. Wash (no fabric softener), dry and iron the fabric.
Lay on a wax paper surface and coat with a thin layer of Fabric Mod Podge. You can do it on the front or back, doesn't matter (for whatever reason I always do it on the front).
After that has dried, cut the fabric to fit the surface. The Fabric Mod Podge you applied will prevent fraying and make the fabric act more like paper! It's pretty cool. NOW you can decoupage the fabric to the lampshade with the Mod Podge.
Allow the first application to dry and then put down a few more coats. Embellish to your heart's content and then allow to dry for at least 48 hours. “Let there be light!”