Most French enhancement techniques teach the tech to apply white at the free-edge and create the smile line. Then the pink is added to the nail plate and the two are connected. In a reverse application, you add the pink to the nail bed and create a reverse smile line. Some let this dry and file it clean and smooth before adding a form and the white extension. The benefit to this technique is being able to push the white directly against the pink to create a clean line. This technique was originally created for applying cover pink powders. It can also be beneficial when sculpting gel.