Place it at the end of a fail sequence, after the mistake and before the reaction shot, then follow it with Hello Darkness My Old Friend for a second beat or Directed by Robert B. Weide to close the scene with a classic freeze-frame ending.
About this sound
This is a short, downcast musical cue played on soft, wavering notes that sink rather than build. It feels gently pathetic and comic at once, like a tiny funeral for a plan that never stood a chance. It is the sad music linked to SpongeBob SquarePants, used when a character's hopes collapse.