Answer:
Steals an event or even a mood. Reveals the truth or shatters it.
Round as a button, deep as a well. If you want me to talk, you must first pull my tail.
Always wax, yet always wane: I melt, succumbed to the flame. Lighting darkness, with fate unblest, I soon devolve to shapeless mess.
We are five little objects of an everyday sort, You will find us all in a tennis court.
What I am filled, I can point the way. When I am empty. Nothing moves me. I have two skins. One without and one within.
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?