Put it at the end of a setup where someone is asked again, then follow it with No No Wait Wait for a longer refusal, or cut to Oh My God Wow when the other person reacts in disbelief.
Over dit geluid
This is a voice clip lasting just over five seconds in which a speaker repeats 'nao nao' with growing insistence. It feels comic and exasperated, like a refusal that gets funnier each time it is repeated, and it works as a quick, blunt answer when a longer explanation would spoil the joke.