Put it right after the failed moment in your edit, then follow it with the Ba Dum Tss Sound Effect for a punchline or the Mission Failed Meme Sound when the attempt is truly over. For a harsher roast, swap in Oh Brother This Guy Stinks instead of a second reaction.
About this sound
This is a ten-second clip of a crowd booing together, with many voices jeering in long, drawn-out boos that fill the room. It feels instantly embarrassing and sarcastic, turning a small mistake into a public flop in front of an audience. The sound lands fast because everyone recognises the jeer at once, so the reaction needs no explanation.