This has a few other advantages as well:
- Smoother line: it's a little easier to make a smooth line with this method than with a continuous line;
- Better shape: in the same vein, it's easier to control the shape of the line as you'll go back over the liner to create the shape and will have fewer chances of whoopsies should your hand veer off path.
As mentioned above, what you end up doing is making those little lines, which can overlap, as close to the lash line as you can. And then you can go back over them in a continuous (or nearly continuous) line.
For the upper lid, I typically do the dotted line starting about mid-eye and going towards the outer corner and then will work my way back from a little off from the inner corner to the middle of the eyelid. When I do the continuous line, I will start from the inner corner to the outer corner (and I flare the line).
This method works especially well for the lower lash line, if you want to apply at the lash line instead of on the water line. It helps to go under the lashes to do this. I start from the outer corner and will work my way inward. I have taken lately to ending this line around mid-eye, which makes my eyes look a little more open (a full line closes the eyes).
This application is nearly impossible to do with a liquid liner, though (unless it uses a felt tip applicator). But it works great with a pencil or gel liner.