Why Don’t You Turn Her Over?

Jim and Fred are at the local pub discussing the respective sex lives.
“Well,” says Fred, “truth be known, I’m just bored with screwing the same hole night after night after night. I guess I’m hankering’ for a bit of variety.”
Jim replied, “Well, if you want variety, why don’t you just, you know, turn her over every now and again?”
Fred says, “What? And have a house full of kids?”