"What do you mean, you can't whistle?" Sokka frowned.
Azula sighed exaggeratedly. "Surely you're not deaf as well as a blockhead? I. Can't. Whistle. Mother thought it was unladylike, so I was never allowed to learn it. It was severely frowned upon at the Royal Fire Academy for Girls. Li and Lo abhorred it. I wasn't allowed to learn it, and so I didn't. And neither did anyone I know. Except Ty Lee, of course, but she's hardly a lady."
Sokka threw his head back and laughed heartily. "Ha ha ha! That's the funniest thing I ever heard! The Fire Nation Princess, famous prodigy, can't whistle! Oh, that's priceless."
He slapped his knee and hollered with glee. Azula regarded her betrothed with flaming cheeks. Blue fire appeared in her hands. She raised them threateningly.
"Keep that up, and I'll really give you something to holler about!"
Sokka wiped tears of laughter out of his eyes. "I… I… Oh, I'm sorry, Azula. It's just that… ah, ha…"
A flash of lightning from the amber eyes. He checked himself hastily and swallowed in an attempt at gravity. Instead, he rose.
"Ok, Princess. You can't whistle. Well, I'm a great teacher to the needy. Now, watch and learn."
Pushing two fingers in between his lips, he blew forcefully, producing a sharp screeching noise. The tiny wolf cub, who'd been sleeping peacefully in its wicker basket, prickled its ears and bounced out to start running around in a frenzy of yipping.
Azula grimaced in disgust. "Why, that looks perfectly obscene! No wonder I was forbidden to learn it. And now look what you've done! When he's in that state, he won't stop barking until we all go out to play fetch in the snow."
"So, we'll go out and play, Azula! After you've learned to whistle, I mean."
She shook her head. "I absolutely refuse to learn to wolf-whistle. In fact, I rather thought you meant the other kind of whistling. You know, the one where you make tiny melodies. Kind of like birdsong."
"Like this?" Sokka pursed his lips together to produce a chirping sound. Happy notes reminiscent of Fire Nation springtime rose towards the ceiling of the hut.
Azula nodded slowly. "Yes. That's much better. In fact, it's rather easy on the ears. I think I like it. All right, snow savage. You may teach me how to whistle like a bird."
"Ok, Princess. It's real easy. You just put your lips together. Like this." Sokka pursed his lips. "You just put your lips together and blow."
Their eyes met. A spark of understanding passed between them.
Azula grinned. "All right, Sokka. I think I can manage that."