>>11362991
I like this idea a lot.
Perhaps this society believes that evil spirits wish to rape their daughters. To keep their daughters pure, the shrine maidens must take turns being sacrificed.
This means being positioned in a public area, mostly naked, and in a humiliating position. This is to make it clear to the fiends what the acceptable target is. It's also allowed for men of the town to use these sacrifices - after all, they are fiends too.