That's what she said.

Had an elderly man as a patient for some years. He had mild dementia. When he would need a blood draw or a shot, he would waggle his eyes suggestively, and would reply "that's what she said" to anything I said. In front of his wife. And his daughter. After some years he kicked it up a notch with "that's what she said, and then the bed broke!"

Some years back, under murky circumstances, his wife accidentally backed over him with their car.