[Byleth liked bright eyed and bushy tailed Shez, caught up in his enthusiasm and pleased that his suggestion had gone over so well. He hadn't been sure if Shez would've approved, but it was nice to know that his feelings had been so well recieved and understood!

Maybe it was a good thing, Byleth kept those thoughts to himself, rather than saying them aloud... imagine what the people passing by this alleyway would think was going on here...]

I knew you'd understand my intentions, Shez.

[Said so warmly and with a pleased smile! When Shez held out his hand, he surrendered his whistle without hesitation, trusting him with it - well, technically, it had been his in the first place, so it was well within his rights to rescind the gift, but he knew that Shez wouldn't take the whistle and run.]

Though, may I ask what you're planning on doing? I'm not the most creative, so I can't think much beyond carving my name...

[He wants to match whatever Shez did! If he did something spectacular, then it'd look boring if Byleth only carved 'BE'!]