What are waterlines? They are exactly what they sound like - the part of your eyelid that actually touches your eye and yes you can actually line the top one! If it doesn't freak you out to do it, lining your water lines can really make some beautiful eyes. Lining your top waterline will really make your mascara look better too as it will make your eyelashes look thicker and darker at the roots.
Most people line their lower water line with a darker liner (black or brown - sometimes color) to create a more dramatic eye (typically smoky) like this:
Here is a more toned down but still lined eye:
If you watched the 4 minute makeup tutorial then you saw an example of lining the lower line all the way while only doing part of the top for a nice everyday look.
My personal favorites are the following:
1. Lining the top lid's waterline for everyday (leaving bottom one untouched) like so:
2. Lining the top one with a dark liner while lining the bottom one with a white liner or powder (you can use an eyeshadow!) to create bigger eyes - more the babydoll look. I usually use the white liner on the bottom for pictures as it creates a really nice eye (eyes look smaller when you use a darker liner on waterlines).
As you can see, waterlines can be hugely important in your eye makeup! So, what's your favorite look? What would you like to see a tutorial on?