Well… most folks’ lips are three dimensional to start with. But the problem with smacking on only one shade of colour, especiallyly matte ones and you’d stand the risk of getting a very flat appearance.
Think drawing a picture with and without shading in light and shadow. Cartoonish no?
What’s more, visually reducing the size of your lips with dimensional shading also creates the illusion of a slimmer jawline. Try it to believe!
The secret is actually to use multiple colours in similar tones (you don’t have to if you’re into bright ombre fashion) and gloss!
Of course knocking off the gloss bit for matte lips works fine too albeit not as effective
Alternatively, for colour-shy feministas, swapping your lighter coloured base colour for concealer works too for a more natural look.
Saw a similar idea in a magazine the other day with the concealer version below: