twiddle thumbs

To wait idly because one cannot take action or has nothing to do at the moment. Although the phrase refers to an actual movement of the hand (in which one's fingers are interlaced and each thumb is brought over the other in succession), the phrase is usually used figuratively. I'm just twiddling my thumbs here in the ER, waiting for someone to give me an update on Claire's condition.

Fig. to pass the time by twirling one's thumbs. What am I supposed to do while waiting for you? Sit here and twiddle my thumbs? Don't sit around twiddling your thumbs. Get busy!

To do little or nothing; be idle.

To be bored; to be idle. The habit of idly turning one’s thumbs about each other during a period of enforced inactivity gave rise to this cliché, which began life in the mid-nineteenth century. “You’d have all the world do nothing . . . but twiddle its thumbs,” wrote Douglas Jerrold (Mrs. Caudle’s Curtain Lectures, 1846).