Put it in the middle of a fail edit, after Sudden Suspense has built the tension and before Knuckles Oh No closes the joke. For a physical gag, follow it with Cartoon Slip Sound Effect instead, so the slip lands as the consequence of the mistake just shown.
關於此聲音
This six-second clip is Scooby-Doo saying his mangled version of uh-oh in a shaky, cartoon-dog voice. It feels like a goofy, lighthearted warning that something has just gone wrong, without any real danger behind it. The line comes from the Scooby-Doo cartoons, where the dog's rhotacised speech turns a simple alarm into a joke in itself.