'Advice' given when a woman will inevitably be taking part in unwanted but mandatory/inevitable sex, usually with a partner but sometimes attributed to rape.

Apparently the phrase began in Edwardian England, when mothers would give it to their daughters on their wedding nights- this would be then first girls had heard about sex. Basically, think of the good the children could do the country (could become soldiers, doctors, etc).
No matter geographical location, 'England' should always be used- don't go about saying 'lie back and think of 'Murica' or 'lie back and think of India'. People will think you're a right ninny.
Sue: Ugh, Brian's convinced me to sleep with him tonight.

Anna: You'll be fine... Just get it over with. Lie back and think of England.
by YourMother'sUnderwearDrawer August 31, 2013
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face it, you're gonna get screwed.
when james told me he was going to join bally total fitness, i told him to lie on his back and think of england.
by Kfifty July 1, 2005
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