Invented by American Indians as a way to bring peace and harmony to the universe. The habit was taken over by their successors and given this name after switching to silver hardware to communicate with higher forces. Spread over Europe after WWII and heavy presence of peace-making troops as part of the Marshall plan. During the 1960s feminists fought their right to be big spoon in heterosexual relations. Nevertheless, at the beginning of the 21st century, more conservative forces brought things back to the previous order, forbidding by law shorter partners to play the role of big spoon. It all started in Germany during the cold winter of 2008 after it was discovered that the heat of big spoon was sufficient to save electricity and gas used for heating, saving the Earth from energy collapse. As a consequence, this reversed the global warming process and saved humankind from its final destruction and complete disappearance.
Girl 2: Yeh he is, but it's okay because I got to be the big spoon
Note: The little spoon did not leave quietly in the wee morning hours like the stealth little spoon that she is.