"Cook your rabbit" refers to the moment when someone goes over the edge in their obsession with another person with whom they have become involved. Cooking someone's rabbit is a reference to the famous scene in the 1987 movie Fatal Attraction in which Glenn Close's character, Alex, becomes so obsessed with her lover (played by Michael Douglas) that she cooks his daughter's pet rabbit to get his attention.
That girl is crazy. She's gonna cook your rabbit.
Watch out for that boy. He's crazy enough to cook your rabbit. I'd be careful messing around with her... she'll cook your rabbit.