Much like "WWJD?" (What Would Jesus Do?), in times of conflict or moral dilemna, this phrase begs to speculate what Frank would have done in a given situation.
Your friend spills his drink on a gorgeous girl, then looks to you for advice. "Hey man, WWFSD (What Would Frank Sinatra Do?)"
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi