[LeratoAustini]

To save others the search: Colportage is the distribution of publications, books, and religious tracts by carriers called "colporteurs" or "colporters"

[bluebarbet]

"Colporter" is not an especially fancy word, it just means "to peddle" in English.

[DicIfTEx]

And for anything you really need to keep hidden, there's always culportage.