Attach the artificial eye to the skin using Grimas Mastix Extra.
Protect the eyes by closing them and covering them with a tissue. Can cause serious damage to the eyes.
MASTIX EXTRA = Mastix Extra

Add a thin layer of Derma Wax on the area around the artificial eye.

By scraping it out, you already make the texture a bit flexible.
You then make the wax easier to model by applying it to the ball of your thumb and scraping it off again with the spatula two or three times.