This technique involves pretending to work while actually not doing anything productive. It's like a digital-age, corporate version of "playing dead" in the animal kingdom. Simply stare at a spreadsheet, pretend to type, and hope no one asks you what you're doing.
While in the "Fake-Work" state, periodically jump up from your seat and perform an exaggerated, awkward dance, like a robot in a disco. This will distract your coworkers from your lack of productivity and make them wonder what kind of "work" you're doing.