There was an older man who'd married a younger woman. All was going well... except in the bedroom. He couldn't last long enough to satisfy her. She said it didn't matter but he knew it was getting her down. So he went to the doctor and asked for help.
The doctor recommended that he satisfy himself before they have sex -- that way, he'd last longer. The next day, the man planned on ravishing his wife when he came home, and decided to please himself on the way. So he pulled over onto a quiet road. But he couldn't just sit there in his car having a wank, so he decided to lie under the car and pretend that he was fixing he car. He crawled under the car, closed his eyes, imagined his wife naked, and started wanking. After a while he felt something tugging at his jeans.
"Sir, this is the police. Would you mind telling us what you're doing?"
Not wanting to lose this wonderful image of his wife he kept his eyes closed.
"I'm just fixing the axle of my car, officer."
"Well, while you're down there you'd better check the brakes. Your car has crashed into a tree half a mile down the road!"