If you haven't heard of a sensory box, this is a godsend. You can make them out of anything (sand, rice, beans, rocks, water, etc.) They are to help you overcome any anxiety you might have with different textures. I used rice in this example.
We had recently gone for a nature walk in the park, where we picked up leaves, acorns & a weird looking seed pod covered in spikes. I googled the seed pod, turns out, it hails from a sweet gum tree. So that was something new we learned. I added some old pinecones, since we didn't find any new ones, and an old dried out gourd from last year. When you shake the gourd, it sounds like a maraca. The seeds are dried inside. So that added to the sense of hearing.
This was literally 20 minutes of serious quiet time. The boys were so into this, they just vegged out and got into the textures. They liked pouring the dried rice into the pine cones and pouring it out the best.