For your lashes, and some guys use it too! Then the liner pen for the base of the lashes and the edge of the lid where it meets the eyeball, a little shadow on the lid and you ready to go on the prowl hehe it works on some girls too, as without it some look like there eyes are dead but then suddenly come to life with a bit of slap on.
It's that shit you girls use to fake good looks (in this case, longer eyelashes) in hope that we guys don't notice you're faking it, and thus percie you as more beautifull than you actually is; oftentimes done in hopes of getting male attention. Or simply put; it's fake beauty.
But seriously though, it's those things (kinda hard to describe) you use to make your lashes seem longer and have more volume.
The "eye shadow" you use to paint (sorry I'm not a native English speaker) your upper eye lid with to give it a nice blueish look. I love it when it's used in modest quantities. If it looks like DIY it's a turn-off :-)
Is it stuff/makeup on the eyebrows or is it on the face. I don't know. Enlighten me. I've heard it mentioned. Just didn't think it's important enough to look into. Didn't really interest me. But heck tell us... something I'll learn.. lol