An erection that comes completely out of nowhere and results in women panicing, buying surgical masks, and hiding their children. Also causes people to run from the room once symptoms persist. Treatment includes laying in bed feeling sorry for yourself and social isolation. There is no vaccination for Swine Flu Boner and symptoms can often re-occur.
''Jesus Christ Mr. Brown, what the fuck is that?! Oh god! Gordon's got a swine flu boner!''