Place this clip at the exact frame where the fail happens in your edit, after a cartoon slip for the stumble itself, then follow it with a confused huh to let the second reaction carry the scene forward.
关于此声音
Derpy Rawb is a short reaction clip lasting about 1.4 seconds, built for a quick hit rather than a long build-up. It gives a listener a silly, awkward feeling, like watching someone make a clumsy mistake and not quite know how to respond, which makes that brief moment feel funny instead of serious or tense.