Place it right after the cute reveal, as the first reaction, then follow with Anime Ahhh for a bigger payoff and Anime Ahh for a second beat. Keep it early in a wholesome montage, before any fail or punchline sound, so the sweet moment stays the focus of the edit.
關於此聲音
This is a brief vocal clip of Filian stretching out a soft 'awww' for just under a second. It feels like a genuine reaction to something sweet, warm and affectionate rather than performed, and it gives listeners that small melting feeling you get from a wholesome moment, the kind that makes you smile before you even think about it.