"Sensory processing (sometimes called "sensory integration" or SI) is a term that refers to the way the nervous system receives messages from the senses and turns them into appropriate motor and behavioral responses. Whether you are biting into a hamburger, riding a bicycle, or reading a book, your successful completion of the activity requires processing sensation or "sensory integration." "(SPD Foundation)
The Sensory Processing Disorder Foundation has great information that explains sensory processing differences and what they look like.
Some recipes to try:
1/2 cup baby oil*
4 cups flour
Mix together until the combination resembles fine breadcrumbs. The dough should be moldable, but easily crumble.
*if you're worried about ingestion, you can replace baby oil with vegetable or canola oil
1 1/2 - 2 cups cornstartch
1/2 cup water
Food coloring (optional)
Mix together well.
Oobleck acts like a liquid when being poured, but like a solid when a force is acting on it.