It's every woman's worst nightmare: You're schlepping through the produce aisle in sweatpants when you spot your ex with a hot new chick. First, move safely out of his line of sight. Next, "Pinch your cheeks for an instantly flushed look, then bite your lips and lick them to make them look really juicy," says makeup artist Mally Roncal. "If you're wearing eyeliner, smudge it with your finger for a quick smoky eye." Finally, flip your head over and shake out your hair to get that sexy, bedhead look. Now, take a deep breath, walk right up to them, and say hi.