Place it just before the reveal in an edit, after a build-up sound like Sudden Suspense, then follow it with No No Wait Wait to keep the back-and-forth going and let the second reaction carry the scene.
Über diesen Sound
This is a short Polish voice clip lasting about three seconds, with a single speaker delivering the phrase 'Nie mów' in a firm, cut-off tone. It lands as a blunt, slightly awkward shut-down, the kind of line that stops a conversation in its tracks and makes the room laugh at the interruption. Its directness makes it feel playful rather than harsh, even when the timing is pointed.