(one had) better get on (one's) horse
Said when one is about to or needs to leave. Well, I had better get on my horse. It was lovely to see you, as always. Better get on my horse before I miss my train!
(I'd) better get on my horse.
Inf. an expression indicating that it is time that one departed. John: It's getting late. Better get on my horse. Rachel: Have a safe trip. See you tomorrow. "I'd better get on my horse. Thesun'll be down in an hour," said Sue, sounding like a cowboy.