Put it at the end of a reveal sequence, after the setup clip has shown what went wrong. Follow it with Emotional Damage for a bigger fallout, or place Bruh just before it to build the disbelief in two steps.
About this sound
This is Seu Madruga's single-word 'Nossa' stretched into a slow, deep drawl lasting just over six seconds. The dragged delivery makes the surprise feel bigger, sillier and deliberately overblown, turning a small reaction into a comic pause. It comes from El Chavo del Ocho, the Mexican series where the character became a familiar face across Latin America and Brazil.