Place it immediately after the offending line in a reaction edit, before any commentary resumes. Follow it with a huh sound for the confused beat, then an oh my god wow clip if the moment needs a bigger group reaction to close.
关于此声音
A short voice clip of someone stretching out the question 'what did he say' in stunned disbelief, drawn out over about two seconds. It gives a listener that instant, funny jolt of trying to process something outrageous, equal parts shocked, confused and amused, like your brain needs the line repeated before it can accept it.