I use a smudge pen, a little plastic tube that feeds out a soft piece of crayon-like eyeliner. Yes, waterproof, because I get a little teary-eyed and get a runny mess otherwise. I apply little dabs in the places I want liner, and use a fine flat brush edge to smooth the dabs into a line.
It can take several passes to remove the liner even with a good eye makeup remover (Neutragena), and I often still don't get it all. My old eyes are so sunken that nobody notices, and I don't give a damn anyway at this point in my life.