With that said, lets get to the end of this "tail". The first few step of creating a thread tail are just like working on the mane. Cut your embroidery thread in half, then in half again for smaller models. For trad scale models, you might need the length and won't need to cut the thread the second time. Comb out the thread and you did during the steps for the mane. Glue one end of the groups of combed thread, cut th glued end across evenly, then cut into the threads perpendicularly, making each cut approximately 1/8 to 1/4 inch apart.
Your model should be "hair prepped", meaning you have removed the original tail and created a tailbone of wire and epoxy. Make sure that the tailbone is painted to match the color of the thread you will be using for the tail. Begin gluing your small groups of thread at the tip of the tail. Add more glue and more groups of thread, working your way up the tailbone. I like to glue mine on in a "V" shape as I work my way up the tailbone to make sure that the tailbone is covered well.