Place it at the end of a confusing claim, after a Ceeday Huh moment, so the dismissal answers the confusion directly. Follow it with a Wrong Answer Game Show sting to underline that the claim was wrong, then cut to the next scene.
About this sound
This is a short French voice line, about three seconds long, saying 'Ce que tu dis n'a aucun sens', or 'what you are saying makes no sense'. It feels blunt and funny, a direct dismissal that cuts off a rambling argument without needing a longer reply. It suits a moment of pure nonsense, leaving the other person with nothing sensible to answer back.