Touch
Some children seek touch. Some avoid it.
A sequin cushion lets a child decide how much they feel, one stroke at a time: the same movement gives a different texture each way, and nothing happens until they choose to move.
Textures like this meet a child where they are — a first, safe kind of touch for a child who pulls away, and a steady, satisfying one for a child who needs more.
Stroke it. Then stroke it back.