I gave each child a decent sized piece of earthen ware clay. I demonstrated joining techniques. I showed them how to rough up the surface of both pieces of clay to be joined, how to dab on some water and how to wriggle them together.
The last time I used clay with a class, the clay dried out very quickly so I showed them how to keep their hands cool by refreshing them on a damp cloth and air drying them. I gave everyone a plastic bag to keep their clay in whenever they weren't using it.
They were to make a vehicle. I had 1940's and 1960's vehicles up around the room as motivation. They rolled their clay out flat and rapped it around a piece of scrunched up newspaper.
They moulded the sausage shape into a vehicle and went from there.
I stopped the children occasionally to point out new approaches that the children had come up with.
We now wait until they dry, before we fire them.