Instapin
One of Corrin's most important neutral tools is Instapin, which, as its name implies, is using Dragon Lunge to pin to the ground at the earliest point. To do this, input Dragon Lunge, then press the attack button immediately after. If an opponent is right in front of Corrin, they'll be pinned, and you can attack with a follow-up. This can also be used to poke beneath the ledge for two-framing or punishing ledge hangs.