really, its just a small rectangular scrap glued on. The real secret is twisting the eye after its on and attached. That way, you can get either sexy, come hither eyes, or sweet, dreamy eyes!
with my last one, i took a scrap, folded it in half and then glued the two sides together. i let it sit for a minute, then glued the doubled over part (rather than the two raw ends) to the eye on top of the eyelashes at the angle i wanted. i let that sit for a bit. then i cut sort of around the eye with probably a centimeter left, so the curve of the eyelid follows the curve of the eye. i cut two small triangles out so that i can fold the fabric over and glue it to the back of the eye. if you hurry, you can glue it, then pop your eye on and snap the plastic backing into place so it pins your fabric to your eye.
that probably doesn't make as much sense as i'd like it to...