Estée Lauder's fresh new face, Kendall Jenner (who's also just been voted GQ mag's #1 coolest woman FYI), has fronted her first product launch for the maje beauty brand, a mascara primer. Initial reaction: I want it. Second reaction: erm, I definitely don't have a Little Black Primer in my make-up bag ATM, so what exactly does it do, please? We've got a feeling these Qs are universal, so we've done some digging – here are three ways you can use this Jenner-endorsed product...