blow one's lines
blow (one's) lines
To forget or bungle the words that one is supposed to say, as in a speech or play. My mind went completely blank as soon as I stepped on stage, and I totally blew my lines. I had learned the speech off by heart, but I was so emotional that I started blowing my lines about halfway through.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
blow one’s lines
tv. to forget one’s lines in a play; to speak one’s lines incorrectly in a play. There I was in my first major role, and I blow my lines!
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.