The tail does lower a bit. They are not to the friendly teasing phase yet, and he need not rush it, if they ever even get there.

"Of course." Byleth allows himself to be drawn elsewhere by the conversation. He won't push his luck again today. He can tell he isn't in any real trouble, and he wants to keep it that way.

"He would, yes. Never have I met a more enjoyable opponent to cross blades with. Not only is he endlessly skilled, but the joy he takes in it is refreshing." He's hard pressed to find someone who doesn't treat training or swordplay like a grim ordeal.

"Please. Give me some credit, won't you? I am confident in my ability to be an attentive and productive pupil. That aside, I know all the teaching pet-peeves to avoid now." And does he ever. The Blue Lions certainly didn't make his job easier, and that's not even counting those who joined his class later. "I can take whatever you throw at me."

Honestly, he's sincere in that. He can't imagine anything that compares to the many trials of his life coming in the form of a class.