Place it just before the mistake becomes final in your edit, then follow the fallout with the sad trombone sound button for the payoff. For a harder rejection, swap the follow-up for the nope avi sound button and cut straight to the reaction shot.
Über diesen Sound
A short three-second voice clip of someone urgently repeating 'No Mikey, no, no Mikey' in a panicked, pleading tone. The repetition makes it feel desperate and funny at once, like watching a bad decision happen in slow motion and trying to shout it back before it lands.