Place it right after the blunder is shown, then follow with a Damn reaction for a second beat, and finish with a sudden suspense sting before cutting to the next scene.
このサウンドについて
This is a short Brazilian Portuguese voice clip, lasting about three and a half seconds, in which a speaker fires off the slang question 'Porra, vacilação é essa?' at a blatant slip-up. It lands with sharp, incredulous disbelief, the sound of someone catching a mistake in real time and refusing to let it slide.