I have had a few international friends ask about "here" when used at the end of a sentence such as "I could use a little help here!" or "buy me some time here!". I would like to better explain this to them, but my best explanation is that adding "here" gives a feeling of desperation to a sentence. Even if that is a perfect explanation of the meaning (which I doubt), it doesn't provide them with an explanation of when it should or should not be used.
Could you please explain "here" in these sentences?