Sounds like a good guideline to have.

[He looks between Aang, to Appa and back again. Climbing, that's something he can do. He just doesn't have much experience climbing...animals. Living creatures.]

Unless you have a ladder packed up there somewhere, I don't see how you can help me. [Yes, he remembers what Aang said about his Airbending. But he didn't say anything about it working on others.]