This fictionalized scene could have taken place almost anytime during W's post-college "party years" (which lasted until he met Laura).
However, it could have happened during 1968-1969 when he headed for Valdosta, Georgia for 53 weeks of flight-training school at Moody Air Force base after enlisting in the Texas Air National Guard. There, he met a beautiful young woman (whom years later, he could only recall by her first name, "Judy") who took his fancy. According to J. H. Hatfield's "Fortunate Son," p. 46, "He'd get drunk and promise her a big church wedding and all the trimmings, but when he sobered up, he'd say, 'I must have been out of my goddamn mind when I told her that."
However, after he graduated from flight school he left Georgia for active duty in Texas without even saying "good-bye" to his "Georgia peach." (Source, Hatfield again, p. 46).
Bush also has admitted to dancing on bars while drunk (although not in the nude, as some have claimed).
In his 1999 biography, "A Charge to Keep," written with Karen Hughes, Bush describes some wild parties at the Midland Country Club that "advertised 72 hours of open bar." Bush adds, "My friends allege that I showed up in a Nixon mask one year and that another time I dressed as Mahatma Ghandi in a toga that looked like a diaper by the end of the night. (Note to Jay Leno and other comedians who have had so much fun with the George- Bush-danced-naked-on-a-bar rumor. It's not true. The toga costume is about as close as you are going to get.")
-- "A Charge to Keep," George W. Bush, p. 135