Place it after the reveal in an edit, not under the build-up, then follow it with Oh My God Wow for a second reaction beat, or precede it with Ceeday Huh when the confusion needs to register first.
このサウンドについて
Jasper 2 is a 13-second reaction clip, the second entry under that name, made to be played in full rather than as a quick hit. It carries an amused, caught-off-guard feeling, the sort listeners use when a plain reply feels too flat and they want a reaction to say what they are thinking without extra words.