It is one’s duty for the day.
Am I on duty today?
Yes, you are on guard duty.
Are you on?
Yes, I am on kitchen police.
Undoubtedly, there would be situations in camp requiring a sense of humor. A lesson which prepared them somewhat for the blunders and jests of their rookie days was this:
Let us play a joke on a rookie.
All right, what shall it be?
Send him after a key.
A key to what?