I found this story on Futility Closet's blog here.
"In 1878 Queen Victoria invited to lunch an elderly naval officer who was hard of hearing. For a time the two discussed the recent sinking of the naval training ship Eurydice. Then, to turn to a lighter subject, the queen inquired after the admiral’s sister.
"'Well, ma’am,' he replied, 'I am going to have her turned over and take a good look at her bottom and have it well scraped.'
'"The effect of his answer was stupendous,' wrote the queen’s grandson, Kaiser Wilhelm II. 'My grandmother put down her knife and fork, hid her face in her handkerchief and shook and heaved with laughter till the tears rolled down her face.'"