A rather
rude comment one makes to another when they want them to go away. If you are
busy, or find the person
annoying this is something you might say to them.
It's intent is not to get a
laugh, since the meaning of the comment is not very humorous. It is more to make the speaker sound
witty.
If somebody says this to you, say no more, just
leave the speakers presence. But for
goodness sakes, don't take the advice
literally!