Place it immediately after the laugh that breaks the challenge, then follow it with SpongeBob Fail to underline the loser's reaction, and save Dun Dun Dun for the next reveal so the two moments do not compete.
About this sound
This is a short dramatic sting lasting about two and a half seconds, designed to mark the exact point where someone laughs when they were told not to. It feels tense and funny at once, turning a small slip into a moment of mock punishment. The sound works as an instant signal that someone has broken the rules and everyone has noticed.