Place it near the end of a cute reveal, after the visual payoff has landed, so it closes the scene rather than opening it. Open the sequence with Anime Ahh as the lead-in, then finish with Tuturu as the closing reaction.
About this sound
This under-a-second clip is Nanachi's breathy Nnnah, a soft high-pitched hum that lifts gently and drifts away. It feels warm, cosy and quietly affectionate, turning a small moment into something tender rather than loud. The vocal comes from Nanachi in Made in Abyss, where her shy, thoughtful manner makes the sound instantly recognisable to fans.