on the edge of your seat

To be on the edge of your seat means that something very exciting is happening or being told to you and you cannot wait to see what is going to happen next. On the edge of your seat originated when people would go to see a movie in the theater and it would be so exciting or even scary, the person would be on the edge of their seat waiting to see what would happen next. It is now often used figuratively to describe how exciting a story or other situation is.