ants in (the/one's) pants
Said of one who is unable to sit still, due to anxiety, excess energy, or impatience. The phrase is typically used with the verb "have." The kids really have ants in the pants today, so I'm going to take them to the playground. A: "Why is Carrie pacing?" B: "She's waiting for her doctor to call, so she's had ants in her pants all day."