"Golf or Sex?" joke

A friend and I were golfing one day when at the 18th hole this guy comes out of nowhere and asks if he could join us.
I tell him, "Well, we're just about done but if you want to join us tomorrow you can. We start at 8 o'clock."
He said, "Great! I'll be here at 8 o'clock, maybe 8:35..."
So next day he shows up at 8 o'clock and plays scratch golf; he was good. We were going to play again the next day and we invited him to join us.
He said, "Great! I'll be here at 8 o'clock, maybe 8:35..."
So the next day he shows up at 8 o'clock, plays with his opposite hand, and shoots under par!
I'm a bit amazed with this guy so I ask him, "You're a pretty good golfer, beating us with scratch golf and then showing-off by playing just as good with your opposite hand. Just what is you secret?"
He said, "Well...when I wake up in the morning and my wife is lying on her left side, I play left-handed.
Or when I wake up in the morning and my wife is laying on her right side, I play right-handed."
So I ask, "what if she is laying on her back?"
"That's when I get here at 8:35."