He looks surprised when he sees the water come right from her hand like that, but it's not a judgemental sort of surprise. It's just different than what he's seen before.

"So the water is right within your body? I have to carry around a jug or a waterskin instead, or be near a water source."

He could manipulate blood, but he's not going to mention that.

"Although even ink or sweat can work in a pinch."

As for his home, he has some very mixed feelings about it. His home life wasn't the happiest, and some of it was directly related to his waterbending. Her excitement is evident, though, so he can stick to the more pleasant and neutral details.

"The Northern Water Tribe is a very cold place, with many structures made at least partially from ice. There are far more nonbenders than benders, but there are still enough waterbenders around that it's not difficult for children to find a teacher. About seventy or so years ago, there used to be very rigid rules. Female waterbenders were only permitted to use waterbending to heal, and male waterbenders were not allowed to learn to heal, but those rules relaxed after a waterbender girl named Katara challenged the status quo."