Place it after the reveal itself in a reaction edit, not over the build-up. Lead in with the sudden suspense sound for tension, then follow this clip with the kids cheering sound when the moment turns celebratory instead of shocked.
關於此聲音
This clip is a single drawn-out vocal 'oooo' that lasts just over ten seconds, held far longer than a normal reaction. It gives listeners a mix of surprise and playful disbelief, like a crowd collectively realising something at once, and the stretched delivery turns a simple reaction into an exaggerated, teasing response to an unexpected moment.