Our Davy is a super-high-tech automaton with the body of a Greek god and the IQ of an average gerbil. Technically, he's an extension of Jael's equally super-high-tech mansion, and like Star Trek's Data, he responds to commands on cue.
You might think of Davy as the ironic inversion of all the "good wife" figures who appear throughout the novel. When Jael arrives home with the other three J's in tow, he greets them with a tray of drinks, just as Natalie does in the home of the Manland Boss. Gorgeous, childlike, and responsive to Jael's every beck, call, and sexual whim, Davy is a disturbing parody of domestic bliss.