This is intriguing. One of the earliest examples of folk song collection was a monk noting down the songs of flagellants during the Black Death:

http://en.wikipedia.org/wiki/Geisslerlieder

I don't have the books they refer to and haven't heard or seen the song in question. Anyone?

Meanwhile. Somebody pointed this out to me, a song for beating yourself with birch twigs in a sauna:

Tapio Rautavaara: sauna song

The tune is a variant of the daft Norwegian polka known in Scotland as "The Hoy Song" because you shout "HOY!!!" at one point. (You don't in the sauna version).