keep you on the edge of your seat
keep (one) on the edge of (one's) seat
To make one (especially a member of an audience) feel very excited, nervous, or filled with suspense while they wait to find out what happens next. Often said of a movie or TV show. The image is that of one literally sitting on the front of their chair because they are unable to sit back and relax. It's not going to win any Oscars, but the film certainly kept us on the edge of our seats the entire time! The scandal has kept everyone on the edge of their seat waiting to see what details emerge next.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
keep you on the edge of your seatBRITISH or
keep you on the edge of your chairAMERICAN
If a film, programme or performance keeps you on the edge of your seat, it is very exciting and makes you watch with great concentration, wanting to know what will happen next. Based on the Stephen King book, it is the kind of story that keeps you on the edge of your seat throughout. Note: You can also say something has you on the edge of your seat or chair. Saturday night's final had the spectators on the edge of their seats. Note: You can also say edge-of-the-seat before a noun. It's a real action-packed edge-of-the-seat thriller.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012