I taught a lot of Storytime Yoga® for Kids after-school programs in the library from 2006-2008 at Creekside Elementary in my hometown of Boulder, Colorado. On lovely fall days, I liked to get outside. The courtyard was just beyond the school library, and I took kids out, without mats, to do some yoga there on occasion.
I like not using mats sometimes, because a) it makes kids realize that they don't need a mat to practice and no need to purchase one. I work in low-income schools a lot and the have and have not is an issue. So I stress no need to purchase anything to do yoga! Plus I always work in a circle.
Getting into contact with the Earth is big in my book. We are washable! Feeling the Earth, feeling the sun and wind, and looking to localize your body in time and space without a mat is useful sometimes!
I used Aesop fables of Sun and Wind, and many other nature stories outside.
I loved the days teaching at Creekside. So many kids of every socio-economic level everywhere eager to connect with themselves! That's the power of yoga!
Remember, if you are a for-profit kids yoga class, you cannot just read Eric Carle's Very Hungry Caterpillar or any other original work in your class to do yoga with if you do not have permission from the author and publisher! It's called copyright infringement! That's why I use folklore or original stories! Read more about it so you are an ethical yoga teacher practicing asteya as well as not get sued!
Something to think about!
Namaste and have a magical day!