Place it right after the reveal or mistake in your edit, then let the reaction carry the beat. Follow it with the Windows XP Error for a tech fail, or precede it with the Womp Womp Fail for a slower letdown.
About this sound
Uwaaaaaaan is a short 1.3-second Japanese voice clip of a stretched-out crying wail, all one big sob. Heard on its own it feels dramatically upset and funny at the same time, like a minor setback treated as total disaster. The clip comes from the anime Oshi no Ko.