Fishy, I know! Very honored over here.
I started off by deciding on how long I wanted the tail and how wide around I wanted it to be at the widest point and the narrowest point. Then I pulled out my pattern paper and marked these measures down and proceeded to draw what basically looks like a giant beaver tail.
I then divided this up into strips and cut it all out. This ended up being my final pattern.
You'll notice the bottom most piece is not beaver tail like. When I made tail version one I didn't get the shape I wanted keeping the beaver tail layout, it looked more foxish so I redrafted that piece. It's half the width of the bottom section. Also, this shape gave a slight downward curve to the underside of the tail, but I liked that look, so I kept it.
From there I cut out strips of fur in the colors I wanted and then began sewing them together. The bottom piece I cut out twice and sewed on side by side placed as the bottom pattern piece is in the picture. Starting with the bottom most piece I sewed up the long seam on the side and stuffed with batting, which is nice and light and gives the tail a nice swish when you walk. I barely had the hole at the top big enough to get my hand in to shove the batting down, so that's something to consider.
Once it was stuffed, I gathered the top hole and attached a swivel based clip with a small piece of leather. Here's a close of shot of the attach clip.
And that's it. Since Ratty's request got me taking more pictures, I'm also including a shot of the ears I made to wear with the tail.
Sorry the pics are a little blurry.