Mundane Made Whimsical
A character shows the audience that a situation is enchanting by keeping their mouths open in a smile.
Coined by the Nostalgia Critic in his Bridge to Terabithia, it's where someone that that one particular expression to establish an enchanting moment. Their mouths will usually be agape, often in a smile. I think this almost always happens to just kids.
Hello, Unknown Troper. You'll need to get known to lend a hand here.