Step 1. Sing loudly in the back room, where no one can see you.
Step 2. Pause every 15 seconds or so, to peek out and make sure the coast is clear.
Step 3. If coast is clear, resume.
Step 4. If customer slips in without your notice, canter out in cheery fashion, providing subtle commentary as follows: "Whoo-hoo-HOO! That RADIO, which MYSTERIOUSLY TURNS OFF whenever I exit the back room, sure does sound like ME, only more INCANDESCENT and TOE-TAPPING, but definitely ISN'T me! What?! Leaving already? Have a good one!"
Step 5. Repeat from Step 1.
©2009, Nicola McEldowney
The Snark Ascending