This aphorism is often attributed (mainly in urban myth) to Queen Victoria's advice to one of her daughters who was about to get married. A more credible source is Lady Alice Hillingdon, who (according to phrases.org.uk) wrote in her 1912 journal: "When I hear his steps outside my door I lie down on my bed, open my legs and think of England". Lady Alice was married to Charles William Mills, 2nd Baron Hillingdon – a banker and Conservative politician, who sat in the House of Commons from 1885 to 1892.
I once noted (but have lost the source) that Glenda Jackson was quoted, from an interview with Michael Parkinson, as saying: "Women aren't expected to enjoy sex; women are expected to think of England and lie back."
© Haydn Thompson 2017