I have finally figured out the trick to using eyeshadow as a substitute for eyeliner, without it smudging the second I apply it onto my eyelids. The key is to dip an angled brush into some water first. The water allows you to pick up more product and apply it with precision. Use the wet angled brush to apply the eyeshadow of your choice. I’ve noticed that the water helps the eyeshadow stay on much longer and makes the colour more pigmented.
I am currently using the elf angled eyeliner brush with the eyeshadow Crave (a matte black) in the Naked Basics palette by Urban Decay. Both are great products to achieve this look. This look is great if you are looking to get a soft line without going for the full liquid or gel eyeliner effect.