[Angry bird...? Like a wyvern, maybe. Felix feels significantly less uncomfortable here knowing Sylvain's on his way, although he certainly doesn't let his guard down. Just in case.

He looks up at the approaching footsteps, his own lips curving slightly upward and a bit of tension going out of his shoulders when he spots Sylvain.]

Better that than grinning like an idiot all the time. Which one is this, the 'I've done something stupid and I don't want Felix to know about it' grin?

[The alternative is that it's an 'I'm genuinely really happy to see you' grin, and Felix isn't sure what to...do, with a thought like that.]