telegraph (one's) punches
1. To make a clear but unintentional physical indication of where, when, and how one is going to throw a punch. You've got to stop telegraphing your punches like that, or you're not going to make it very far in the boxing world. The guy went to take a swing at me, but he telegraphed his punch and I was able to duck out of the way.
2. By extension, to do something that unintentionally makes it obvious what one's intentions are or next move will be. I was a little nervous about the interview, but the person conducting it telegraphed their punches, so I was able to answer everything pretty easily. The senator has been telegraphing his punches throughout this entire campaign.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
telegraph one's punches
1. Fig. to signal, unintentionally, what blows one is about to strike. (Boxing.) Wilbur used to telegraph his punches until his trainer worked with him. Don't telegraph your punches, kid! You'll be flat on your back in twenty seconds.
2. Fig. to signal, unintentionally, one's intentions. When you go in there to negotiate, don't telegraph your punches. Don't let them see that we're in need of this contract. The mediator telegraphed his punches, and we were prepared with a strong counterargument.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.