His father did. I am powerless to stop it, so I just document.
I think Josh was trying to encourage some more manly fun. He gets a little uncomfortable with Derek's knowledge of all things princess.
Here he is singing a rather unrecognizable version of his favorite song: "Sing Sweet Nightingale" from Cinderella.
Don't worry Josh, I promise not to let him wear any tutu's while you're away.