Quetzalcoatl is a Mesoamerican deity whose name comes from the Nahuatl language and means “Feathered serpent”.
The worship of a feathered serpent is first known documented in Teotihuacan in the first century BCE or first century CE. The creature is associated with Mayan, and later, Aztec culture.
At temples such as the aptly named “Quetzalcoatl temple” in the Ciudadela complex, feathered serpents figure prominently and alternate with a different kind of serpent head. The earliest depictions of the feathered serpent deity were fully zoomorphic, depicting the serpent as an actual snake, but already among the Classic Maya the deity began acquiring human features.
The Plumed Serpent begins as the title of A D.H. Lawrence novel set in Mexico.
The title is a reference to the cult of Quetzalcoatl, the plumed serpent.
Then comes serpent as slang for penis, and that gets you to a gay bar.
Note 2: A memorable schlocky movie of my childhood was The Flying Serpent,.
Source: Arnold Zwicky’s Blog