Place it just after the confession line in an anime edit, then follow it with Awkward Moment to underline the pause that follows, and save Onii-chan Onii-chan for a later teasing beat so the two voices do not compete for the same reaction.
About this sound
This is a short anime voice clip lasting about 5.6 seconds, built around a single spoken line delivered in a light, teasing tone. It feels playful and a little flustered, the kind of quick reaction that lands best when a conversation turns suddenly sweet or awkward, and the delivery itself carries the moment.