Wiktionary
vb. 1 (context intransitive English) To set and cinch a saddle on a horse in preparation for riding. 2 (context transitive English) To set and cinch a saddle in preparation for riding.
Wikipedia
Saddle Up is the first and only album by the band First Arsch. It was released in 1992.
Usage examples of "saddle up".
What a miserable world it is that makes scholars saddle up for war.
She heaved the saddle up onto her left arm, supported it with her right, and ran to the horse corral.
My old daddy always said that the purpose of breakin a horse was to ride it and if you got one to break you just as well to saddle up and climb aboard and get on with it.
It won't take that long, and regular travel uniforms are appropriate, but your men won't need to saddle up.
It had been one of Krystal's guards, going out to saddle up and get ready for the ride to Kyphrien.
Maybe the Captain would just saddle up the Hell Bitch some night and go.