Nothing new about this subject. The double entendre riddle has been around a long time due to its popularity. This one, from my dog-eared and frayed copy of Penguin Classics' "The Earliest English Poems" is a translation from around the 8th century, possibly earlier:

Swings by his thigh a thing most magical!
Below the belt, beneath the folds
of his clothes it hangs, a hole in its front end,
stiff-set & stout, but swivels about.

Levelling the head of this hanging instrument,
its weilder hoists his hem above the knee:
it is his will to fill a well-known hole
that it fits fully when at full length.

He has often filled it before. Now he fills it again.


The answer of course:    a key.


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