I recommend the Make Up For Ever Aqua Resist Color Pencil.

I have a spring warm undertone, so I only use brown eyeliners.

I don't have double eyelids, so my eye makeup smudges easily.

Since turning 20, I've tried all sorts of products looking for a smudge-proof eyeliner, and this is the best!

It applies quite thickly, and since it is a brown without any reddish undertones, I like that it doesn't make my face look puffy.