It can be used in a variety of contexts, for example:
* "I'm dun with my homework." (Meaning: I've finished my homework)
* "That's dun, let's move on." (Meaning: That's finished, let's move on to the next thing)
* "He's dun talking about it." (Meaning: He's finished talking about that topic)
It can also be used as a general expression of agreement or acknowledgment, similar to "okay" or "got it."
It's important to note that this slang term is often used in casual conversation and may not be appropriate in more formal settings.