Final answer:
The specific action the narrator proposes to Robert cannot be determined without further context from the story or novel being referenced.
Step-by-step explanation:
The question appears to be about a story or novel in which a character named Robert is present and the narrator's wife suggests or intimates an activity for the narrator and Robert to engage in after she leaves them together.
However, without specific details from the passage or context regarding the story's characters or plot, it is impossible to precisely determine what the narrator proposes to Robert.
In literature, various narrators and characters have different dynamics, and the activities they propose can range widely depending on the context within the narrative.
To offer a thorough and accurate response, more information about the particular story and the actions leading up to this event would be necessary.