roll in the hay

Don't disturb them. They're having a roll in the hay, I think.

But hay-makers would rather be without one [a rain fall], and if it were wet weather, that gay party of children would not be able to enjoy their roll in the hay. I think they are going to cover that little boy with hay, and then he will jump up and serve them the same. Their gambols do no harm, as the more the hay is scattered and shook about the better, and the hay-making, which began last month, is now to be finished.