A phrase employed as a last
ditch effort to save yourself in an arguement, avoid
work,
insult someone or simply when you have nothing else better to say.
Alex, did you do the rest of our very important project that's due
today?
Errr..
You DIDN'T do it?! I can't
believe how irisponsible you are!
I didn't do the project, but I did do your
mom.