I'm not talking, like... SUPER tiny or anything. Just... normal for his body type? And definitely not as large as Gladio's. But it fits comfortably in Gladio's mouth, which makes giving head really easy, and he can wrap his entire hand around it, and it's getting fucked by him too. Like Noct was made for him, or something.
Gladio/Noctis - Gladio actually really likes Noct's small dick