between you and me and the bedpost/gatepost/four walls/lamppost

between you and me and the bedpost/gatepost/four walls/lamppost

In strictest confidence. This elaboration of just between you and me is often followed by gossip about someone else. The bedpost version dates from the early nineteenth century and was used by Edward Bulwer-Lytton (Eugene Aram, 1832: “Between you and me and the bedpost, young master has quarrelled with old master”), Dickens, and others. The lamppost version may be a little older, but is not much heard anymore.
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