#flashipping

Gakuto: "Anyway! It is dangerous! So, please get off the machine and duel normallyyyyy …!"

Yuuro: "Normally, huh …. You're really fine that way?"

Gakuto: "Sorry?"

Yuuro: "I know it. About the real you, it is …."

Gakuto: "The real … me …??"

Reasoning: Gakuto had the habit of saying 「パーっと」 'paatto', which could mean 'shining', 'quickly', 'in a flash', 'lavishly', 'grandly'; it could be associated with light and speed—in his case, it mostly meant shining or lavishly, though. While, Yuuro was associated with speed and had the habit of using the word 「音速」 'onsoku' a.k.a. 'sonic' or 'speed of sound', like saying "summon monster in sonic speed", and calling himself "sonic duelist"—at least in Duel Links. Both light and sound were associated with speed, and so is "flash".