"What do you need boy robes for?" inquires Madam Malkins.
"I'm sometimes a boy," the girl explains.
"What?"
"Look—"
He will be greeted by what's possibly the coziest place on Earth.
There's a fireplace and a huge rug that feels like it hugs you when you walk on it and several sofas and a couple of bookstands and people, all of the Hufflepuffs are there, telling each other stories, playing cards or more arcane games, greeting the new firsties.