Used as a noun, Douche Bag is a title earned by, most commonly, men who are...
Selfish, Narcissistic, Obnoxious, and/or mentally insane.
Douche Bags are most commonly: Chads, Clout Chasers, Attention whores, and Fags
Person 1: "did you hear what Connor did to Janie!?"
Person 2: "omg what happened!?"
Person 1: "Connor asked Janie on a date and she rejected her, so he spread a rumor that she sucked off LeBron"
Person 2: "What a Douche Bag!"