A servant girl sent for barm comes back with a tale of mishaps from the young men in the street. The tumbling rhythm and comic misfortune are the whole point, and the title's irony is part of the joke.
From Mother Goose / Nursery Rhymes (traditional). See the whole collection.
Trip upon trenchers,
And dance upon dishes,
My mother sent me for some barm, some barm;
She bid me go lightly,
And come again quickly,
For fear the young men should do me some harm.
Yet didn't you see, yet didn't you see,
What naughty tricks they put upon me?
They broke my pitcher
And spilt the water,
And huffed my mother,
And chid her daughter,
And kissed my sister instead of me.
Public domain. Text from The Real Mother Goose (Blanche Fisher Wright, 1916), via Project Gutenberg. View the source edition