Well, "Not tonight, Josephine," is a quote supposedly from Napoleon (when declining to sleep with his wife... like Whitney does later in the movie!), so maybe it's just idiosyncratic command syntax? Also, it plays "La Marseillaise," the French national anthem, furthering the connection. Not sure why it's eaten by a shark, though.
Regarding Rick's relationship with his mother, when she questions him about his grades, he distracts her by hugging her, picking her up and spinning her, and telling her she has a great ass[!]. His mother not only laughs this off, but says, "It sure is a good thing you're cute, kid." The whole thing is disconcertingly flirty.
Also, earlier in the same scene, his sister explains that she's late because she had to go to the 7-11 and was held up comforting a woman who was apparently in labor, but the baby never showed up so they took her home? This is yet another baffling scene that is never brought up again but can be shrugged off the explanation of "It's Florida."