You must have seen this kind of scene in some media or other: a film noir-style private eye is napping or brooding at his desk. The door opens and in walks a vampish dame; she’ll likely be richly dressed and there may be a view on her from her legs upward. She comes in and says she has a case for him, and the story develops from there. I’ve seen this situation in enough works to surmise that we are dealing with an established trope. Not surprisingly, it can be played as parody; a good example is the few arcs in the comic strip “Calvin and Hobbes” where Calvin imagines himself as the cynical, Byronic PI “Tracer Bullet”; in one arc the dame that walks into his office is revealed out-of-imagination to just be his mother; in another arc, it was IIRC his imaginative stand-in for his classmate Susie Derkins.
Where does this trope originate? Is it by any chance the film “The Maltese Falcon” (or perhaps a scene in the novel that it was based on?) The opening scene of the film (see here) indeed shows such a scene, though admittedly, the woman with the case (Brigid) doesn’t seem as vampish (think Veronica Lake-, Lauren Bacall-, or Jessica Rabbit-like) as in the later spoofs and parodies that I’ve seen.