The man decided, "What the heck, I'll try it."  He spent the rest of the day
thinking about where
to do it. He couldn't do it in his office.  He thought about the restroom,
but that was too open.  
He considered an alley, but figured that was too unsafe. Finally, he
realized his solution.  On the way home from work, he pulled his 4X4 over on
the side of the highway.  He got out and crawled underneath as if examining
the vehicle.  Satisfied with the privacy, he undid his pants and started to
masturbate. He closed his eyes and
thought of his lover.  As he grew closer to orgasm, he felt a quick tug at
his pants leg.  Not wanting to lose his mental fantasy or the orgasm, he
kept his eyes shut and replied "What?"  He heard, "This is the police.  What
in the hell are you doing?"  

The man replied, "I'm checking out the rear axle, it's busted."  The cop
says, "Well, you better check your brakes too, because your 4x4 rolled down
the hill 5 minutes ago."