Put it at the end of a fail sequence as the final reaction, then follow it with the Bruh Sound Effect for a deadpan beat, or with Emotional Damage Meme Sound when the loss is bigger and deserves a longer payoff.
About this sound
A cartoon voice blurts out 'oh what the f' and is cut off mid-word in this sub-second SMG4 clip, leaving the swear unfinished. It gives a jolt of disbelief and embarrassment, as if a plan has just collapsed on camera. It comes from SMG4, the long-running comedy series built around chaotic Mario-inspired parody videos and exaggerated cartoon reactions.