... "our posteriors"...
I'm drawing a blank, but can offer this...
Nothing so erudite. Carry on Cleo. KW as Caesar after the dust up at the Temple of Vesta, same scene as "Infamy, infamy..."
Caesar, "I cannot go without saying something for posterity."
Calpurnia, "No, dear. Of course you cannot."
Caesar, "Then let our posteriors know this..."