a cat on a hot tin roof
One who is anxious and unable to sit still or relax. A: "Why is Carrie pacing?" B: "She's waiting for the doctor to call with her test results, so she's been like a cat on a hot tin roof all day."
cat on a hot tin roof
A Southernism that meant someone who was on edge or nervous. The phrase survives as the title of Tennessee Williams's 1955 Pulitzer Prize–winning drama.