Two things!

First, our tail is going to wag back-and-forth... a tight fit may have an undesirable result - felt loosely for free-flowing movement.

Second, watch the angle of your felting needles. We don't want to damage the tube underneath or break a needle on a hard plastic piece.

Especially on the tip of the tail.

You could attach the tail directly to the body... but for sake of serviceability I'm going to make a 'port' for the tail to slip-through.

If you need to service anything inside Wizzy, all you will have to do is loosen one screw (neck base / servo) and slip the body over the tail. 

Seams can be hidden fairly well if you build-up the rim until it's snug around the tail.