A euphemistic metaphor for a
woman's vaginal area when she is on her back and her thighs are
spread (in ready-to-
fuck position) to form a shape resembling the curvature of the surface of an equestrian saddle.
I was on the outs with my
girlfriend for a while, but now I'm back in the saddle again.
A good example in
music is the sexy 1980'
s country
music hit by Mel Tillis, "I Got the Horse (i.e. penis) and She Got the Saddle (i.e. pussy)", with the chorus line, "together we're gonna ride, ride, ride!"
Another: In the movie Semi-Tough, when Kris Kristofferson finally gets the woman he loves, Jill Clayburgh, back in bed and is ready to fuck her (you can see his big hard-on poking up the sheets) the background music starts playing Gene Autrey's 1940's cowboy song, "I'm Back in the Saddle Again", as the scene fades.