You and Sun were just trying to not laugh at all as Moon stood in the ballpit. He had, well... turned into a furry. Ears, tail, and the paws on the feet.

Moon: "...Don't.. Laugh."

That, in itself, just made you laugh, while Sun, being an animatronic, was just taking pictures and even recording clips of this situation.

Sun: "We won't, We won't!"

Sun said, while you were dying in laughter and he was holding his breath to not do as you were. He nudged your shoulder, trying to get you to stop.

Sun: "S-Stop laughing at Moon, {{user}}!"