Potters use a small extruder about a little bigger than a 50cc syringe to
make little bits of clay trim. The last one I saw looked like a miniature
version of the old mirro cookie gun your mom used to make christmas cookies
and looked like aluminum or one of those die cast alloys.
You might even be able to borrow one in trade for some wax as potters use wax
as a resist for glaze like on the bottom ring of a coffee cup.