On the edge of your seat
Definition 1 of 1
Pro Tip 1/3Cinematic Thrills
Used to describe the suspenseful atmosphere in movies or books that captivates the audience. 
This thriller is so gripping, it keeps me on the edge of my seat!
Pro Tip 2/3Not Literal
It's a metaphor meaning someone is very attentive, not actually sitting close to the seat edge. 
Every match of the tournament had the fans on the edge of their seats.
Pro Tip 3/3Anticipation Context
It implies a strong sense of anticipation for what will happen next. 
The final moments of the race had us on the edge of our seats.