Does a term like "unilukkari" exist in any other language than Finnish?
Lukkari comes from a word for bell-ringer (cogate would be clocker), and uni means sleep.
It was a church officer, something like a sacristan, who would walk among the aisles during service, with a long staff with jangly bits on it, and hit the staff on the floor next to people who had fallen asleep during the sermon.
Part of the explanations I have heard was that people had to get up very early and drive a long time to get to the church, in sleighs during winter, and then getting into the relative warmth of the church would make some people drowsy.