Then it reminds me of what I experienced about 4-5 year ago. A co-worker asked for help about something wrong with his code, regex, to be precise. When I looked at his screen, I wanted to explain about what was wrong with his regex and why it was wrong. Just as I started he stared at me and I stopped immediately. I think that was his "Don't be pedantic. This is not a teachable moment." Only that his statement, more or less, was "Don't explain, just tell me and I'll type" in such expressive way. So that's what we did.
It was like I had a somekind of speech-synthesizer, and he typed whatever I said, well almost :-) "Go to line 24, move the cursor at the opening square bracket, add caret, move cursor over 3 characters to the right, remove that dollar, oh no, sorry, I mean the underscore, the underscore, yes, right. Now, press the ESC, then ZZ. OK, type perl -c add.cgi. Good." (Just FYI, we used vim, well I still do).
Another case is when I was the one who felt the situation. So instead of explaining what was wrong, I said, "follow my instruction and just type what I say." Of course, IMHO, this is not the way for learning process. There's not much (if any at all) for the asker to gain lessons. It's just that in this particular circumstances, the number one and only goal is to have the problem solved.
Update: Now that I have my quota again today, It's please to put ++ on bobf and dana for interesting thread :-)