1 Mordekai: Six hours flight is a long time. Where’s the privy?
2 Alvissa: You can learn to be dainty and elegant like an elf and hold it until we get there.
3 Mordekai: I suspect Dwalin may have a problem with that.
4 Dwalin: Nay! Nay prooblum at all. I joost relieved meself oover thu side.

In all the time they've been adventuring, the first time we hear about them needing to use hygiene facilities is when they're riding on the backs of giant eagles.

And I really laughed when I realised what Dwalin must be doing with his back turned and his arms spread wide like that.