Stevenson turns the nightly business of getting into bed into a small sea voyage, complete with a nurse who "girds" the child in a sailor's coat before they sail off into sleep. The steady four-line stanzas rock like the boat itself, which makes it a natural one to read at the actual moment of tucking in.
From A Child's Garden of Verses. See the whole collection.
My bed is like a little boat;
Nurse helps me in when I embark;
She girds me in my sailor's coat
And starts me in the dark.
At night, I go on board and say
Good-night to all my friends on shore;
I shut my eyes and sail away
And see and hear no more.
And sometimes things to bed I take,
As prudent sailors have to do;
Perhaps a slice of wedding-cake,
Perhaps a toy or two.
All night across the dark we steer;
But when the day returns at last,
Safe in my room, beside the pier,
I find my vessel fast.
Public domain. Text from A Child's Garden of Verses (Robert Louis Stevenson, 1885), via Project Gutenberg. View the source edition