Place it just after the reveal in a short edit, then follow it with the awkward moment cue to hold the reaction before a disappointed reaction finally closes the scene.
About this sound
This is a brief 2.2-second comic sound effect linked to Bonobono, a young blue sea otter who stars in a Japanese manga and anime series created by Mikio Igarashi. It gives a quiet, uneasy feeling of embarrassment and nervous hesitation, as if someone has just noticed a mistake and cannot find the right words. Korean editors pair it with the character sweating to underline secondhand embarrassment.