This is the tail section I printed to go with AZDavros' cybermat head and body. Not perfect but I'm a noob and bending styrene isn't my strong suit.
Have successfully printed this (the tail might be a bit loose but if youre planning a servo to give it a "wag" then youre probably going to be fine).
Smooth with body filler (bondo or bog depending on where you're from) ánd then sand and paint to desired colour. I am using 3mm screws and nuts to fix the sections together (countersunk screws on the top).
This was en experiment in Tinkercad while I was struggling to produce a tail for the RC cybermat.