oh, to be a fly on the wall

Oh, to be a fly on the wall is a phrase used when someone wants to say that they would like to be a fly on the wall in a specific situation because then they would be there secretly and be able to see and hear what happens. This is often used when a situation is going on behind closed doors that they are curious about and would like to know all of the details of, or to see something go down such as a private business meeting.