Currently I use the smashbox waterproof pot eyeliner and a Laura Mercier flat eyeliner brush and I like the look and it has great staying power but damned if that stuff isn't crazy tenacious and doesn't remove easily. I use good eye makeup remover but I think since it's buried deep in my lash line, it's hard to remove so I always end up with some smudge under my eyes. So I think maybe I need to try a different gel eyeliner?
Other stuff I've tried: Still waterproof liquid pen-it was ok but not enough impact
Tarte emphas eyes-dry, crumbly, ineffective
Laura Mercier tightlining cake liner-getting it wet was a pain and I had a hard time getting the correct consistency and it often ended up in my waterline.
Have you tried using makeup remover on a cotton swab to remove it? Just gently "scrub" your lashline with your eye closed. That works for me with stubborn to remove eye makeup.
Honestly, I don't tight line and still have this issue. If I spend enough time with an oil cleanser (all over face and eyes) will actually break it down. But if I don't spend enough time ill have some residue in my lashes.