Matthew Vaber’s life has just taken a turn for the worse. His father has killed himself—a tragedy for which he feels bitterly responsible, when he lets himself feel much of anything about it at all—and his thrilling but damaged mother has taken center stage yet again. Into this cocktail of familial mayhem, Matthew tosses a bubbling new ingredient: the Pump Line, New York’s tawdriest phone sex service, where men appear and disappear with the...