twiddle your thumbs
twiddle (one's) 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.
twiddle your thumbsbe bored or idle because you have nothing to do.
ˌtwiddle your ˈthumbs(informal) do nothing while you are waiting for something to happen: I had to sit at home twiddling my thumbs, waiting for the phone to ring.
If you twiddle your thumbs, you move them around each other while your fingers are joined together.