A couple celebrating their anniversary went back to the bar(pub) where they met. After a couple drinks the wife asked the husband "Do you remember what we did the last time we were here?"
he said "Yeah, We went out back and made love up against a fence." She gives him a sly look and asks "Do you think that fence is still back there?" Only one way to find out. So they sneak round back and sure enough the fence is still there so he drops his drawers and lifts her skirt and backs her up against it. There happened to be a cop sitting in his car up the alley. He's about to go and break up these scofflaws but he is struck by the vigorous, frantic lovemaking, lots of shaking and loud moaning. When they finally break free of each other the cop rushes up and says "That was amazing. how do you explain vitality and physicality of your lovemaking, at your age?" The old boy says "Thirty years ago, that fence wasn't electrified."