There are three different flags people may be talking about....
The Corps of Cadets flag is in Luigi's post about.
The white flag that says United States Coast Guard is the "Coast Guard Standard". That is the flag you will see in parades for the U.S. Coast Guard.
The Coast Guard flag with the vertical red stripes is the "Coast Guard Ensign". There are some laws regarding the display of that flag, it is "for official use only" and may only be displayed by the U.S. Coast Guard. It signifies the authorities of the Coast Guard. I would not recommend displaying it because....it's against the law. I have one that came from my first ship...I don't fly it, just stow it away. It looks like the Customs flag, except that it has a Coast Guard crest....