If you want to draw a line that's thick on your lid but tapers off to a thin line by your temples, this marker will do the trick. Hold it at an angle to draw a wide line, or apply it at a 90-degree angle to your face to create a thin mark using just the point of the pen.
If I know I'm going to have an 18-hour day, I opt for this eyeliner. It won't smudge, and it never creases -- you could sleep with it on (not that I recommend it), and it will look perfect the next morning. Of course, that means it's also extremely challenging to remove. (Try using Kiehl's Supremely Gentle Eye Makeup Remover, $16.50.) The color is extra black, so be prepared for a less-than-subtle look, and the point is medium thickness. And because it will never transfer, it's ideal for experimenting with lines under or over the lid.