When a girl passes out, usually from drinking too much, then one or more males busts in said girl's hair, creating a pool of what resembles a fedora.
Guy 1: "What's that on Emily's head?"
Guy 2: "We all pitched in and got her a Bill Cosby Fedora."
Guy 1: "Thats Emily, always drinking too much and wearing Bill Cosby Fedoras."
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