Saw this mentioned on the article for making a cake pillow but can't seem to find it anywhere. Looks like some kind of extruder and if I can find something that will help making fondant ropes, I'll take it!
I have seen a simple clay extruder in Hobby lobby in the clay section also they have the makin's Ultimate Clay Extruder.
Try this link.
If it doesn't work just type in 20006 in the search bar.
I have it and really like it.
I have two different clay guns, both by Makin's. There is a simple silver one that you have to push and then the there is a green one (I believe it is the Ultimate Clay Extruder) that screws and is A LOT easier to use. Either are available at Hobby Lobby or Michaels. I recommend the Ultimate.