Drawings of Tongues Sticking Out - An Adorable Taunt
When someone sticks their tongue out, they’re either trying to be mischievous, flirtatious, or provocative - or some combination of the three. The general idea is that the pose is used to garner some sort of reaction out of someone else.
Megumin (from KonoSuba: God's Blessing on this Wonderful World!) certainly looks a little impish. Why do you think the other characters below are posed this way?