Really...
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Ben Franklin on the subject (excerpt from his Essay "Fart Proudly"), all emphasis is my own:
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It is universally well known, that in digesting our common Food, there is created or produced in the Bowels of human Creatures, a great Quantity of Wind. That the permitting this Air to escape and mix with the Atmosphere, is usually offensive to the Company, from the fetid Smell that accompanies it. That all well-bred People therefore, to avoid giving such Offence, forcibly restrain the Efforts of Nature to discharge that Wind.
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Franklin was proposing a way to alter the chemical mixture of the "air biscuits" to produce a more pleasing "parfume".
Air biscuits. I lol'd
I did too. That idiom has been summarily added to my lexicon.