When the boss comes in and you're "working" on a important project

My boss has found me teaching customers how to play a variation of solitaire, eating a giant sandwich to which he said "I have never seen a person take that big of a bite - it was like your jaw was unhinged", and found me trying to write an essay for the next day - he still keeps me employed because I get stuff done when it matters (even though he calls me "barely an employee" from time to time).

How do you pin a wave upon the sand?