get on horse
get on (one's) horse
To prepare or get ready to leave. Well, I had better get on my horse. It was lovely to see you, as always. Time to get on my horse—I don't want to miss my train!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
get on one's horse
Sl. to prepare to leave. (Usually fig., with no horse present.) It's time to get on my horse and get out of here. I've got to get on my horse and go.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.