Lip Brush

This is that awesome flat edged brush that I use both for precision liquid lips, and also use to perfect my liquid eyeliner wings. 

To use as a lip brush, use the flat edge to create a continuous line around your lips, and the curved part of the brush to shape your cupid's bow. 

To straighten and correct your eyeliner, with your finger, apply a drop of makeup remover to the edge of a clean brush.  Use that edge to sweep away any eyeliner mistakes.