Place it right after the confusing statement, before the reaction shot or cutaway, so the edit pivots on the misunderstanding. Follow it with Vine Boom when the mistake becomes obvious, or with Dun Dun Dun when the confusion hints at something worse coming next.
About this sound
This is a very short spoken clip, lasting under a second, in which a voice delivers the line 'I don't understand a word you just said.' The delivery is blunt and baffled, turning plain confusion into a punchline. It feels dismissive without being angry, like a shrug in audio form, and works best as a quick reaction to nonsense, jargon, or an explanation that went nowhere.