Much like computers and applications today, you could set sounds to occur when certain functions occurred. One of the sound files we found on the machine was a voice saying, "vroom, dippy-dippy". There was no context. It was a man's voice, somewhat low, serious (not comical or silly), and not excessive.
A few of us began adding it to various random keystrokes. Time to print? Press Command-P. And there was "vroom, dippy-dippy". A few friends used it as an in-joke in conversations. But 30 years on, not surprisingly, I can't find anything about the phrase.
I'm curious if anyone else remembers it. I have always believed it was part of a game, but cannot fathom what it would be.