Place it at the end of a blooper sequence as the final punctuation, after the mistake itself. Follow a tense build with the Dun Dun Dun Sound Button first, then let this clip close the bit, or swap in the SpongeBob Fail Sound Button for a cartoon version.
About this sound
A short clip of someone attempting to whistle a simple tune and failing, with the notes wobbling, weakening and giving up instead of holding pitch. It feels funny and cringingly awkward, the sound of confidence draining away mid-attempt and leaving an embarrassed flop that listeners instantly recognise from real-life mishaps and bloopers.