Place it right at the reveal, then follow it with the Awkward Moment Sound Effect to hold the reaction for a beat longer, or lead into it with the Onii-chan Voice Clip when the scene needs an anime setup first.
About this sound
This under-a-second clip is a sharp, high-pitched anime girl gasp, a quick breath in that sounds startled and over-the-top. It lands as funny and awkward at once, turning a surprising reveal or an embarrassing slip into an instant reaction. The exaggeration is the point, making a small moment feel huge and impossible to ignore.