Don't quite know what they're called. Consists of a tube with a hole at the end (in a variety of shapes - circle, star, triangle etc). You plonk a sausage shape of play do inside, and push it through the hole with another plastic bit that fits inside the outer tube.
Ds loves them (used at toddler group) but I can't find them anywhere. Have tried ELC, Woolies, Smiths, Toysrus. People at toddler group can't remember where they came from.
Need to buy online.