box oneself into a corner

(idiomatic) To create a predicament or problem for oneself; to do something that leaves one with no good alternatives. or solutions.

Example: 2012 May 15, Scott Tobias, “Film: Reviews: The Dictator”[1], The Onion AV Club:
  Brüno was a case of diminishing returns, intermittently amusing but not nearly as bracing or funny as Borat—it didn’t help that Brüno was the most thinly conceived of all his Da Ali G Show characters—and the lead-up to Baron Cohen’s new comedy, The Dictator, made it look like he’d boxed himself into a corner.