"Nothing is wrong about that," William tried to resist the urge to laugh again, and yet he failed this time.
"Stop it!" Sloth was pretty annoyed, especially when William kept looking at him from time to time, smirking and even laughing at some times when they boarded that ship.
The moment the ship moved, Sloth started to grow weak. He leant over the edge of the ship, and held it with both hands while trying to not throw himself off to the ocean.
"Come on! It's not that bad, don't tell me you can't swim, hahaha!" Such a sight of Sloth made William itchy to get out a recording crystal and save this moment for later, forever. Yet he couldn't tell what Sloth would do later when they'd leave the ship.
So he refrained from doing so. And in the end, he controlled and behaved himself, especially when they got closer to the land.