François Rabelais (1494-1553), Gargantua and Pantagruel
III.27 (Frère Jan advising Panurge; tr. M.A. Screech):
If you don't
exercise your mentula, she'll lose her milk too and serve only as a pisser, and your bollocks likewise
will serve merely as game-bags.
Si continuellement ne exercez ta mentule, elle perdra son laict et ne te servira que de pissotière; les couilles pareillement ne te serviront que de gibbessière.
French mentule is derived from Latin mentula = membrum virile. If I were translating the sentence I might introduce the pun man-tool to render mentule. I would also translate the adverb continuellement, which Screech omits.