[After a while, the area Appa is flopped on will be covered in piles of hair, as Aang diligently brushes his fuzzy friend. Once he's done, he turns to the piles of fur lying around, scratching his chin before hopping up on top of Appa's saddle to grab something from there, coming back with a half-sewn toy, cheerfully showing it to Appa]
See, I've got the perfect use for all this hair! [He grabs handfuls of it, and starts stuffing the toy, testing it out by squishing its body.] It feels just like the real deal! [He's a genius, Sokka would be proud.]
Ah, but don't worry, buddy! [He pats Appa's nose amicably] You'll grow it all back in no time, I'm sure.
In fact, [he leans close enough that he's kinda squished against Appa's face, which he doesn't seem to mind, and looks like he's been dying for a good chance to point this out all day] I think both of us are growing hair lately! [He makes a silly face, leaning even closer and sticking out his upper lip to try and show Appa that he's got the faintest, thinnest, ghost of a moustache growing out. Appa makes a rumbling noise of acknowledgment and proceeds to lick Aang, making him fall onto his back, laughing.]
I know, isn't it great?! I think I'm truly starting to grow into this father and grandfather role!