Braid your hair. Braid the ponytail down to the end of your hair.
To braid your hair, start by separating the hair into three strands. Cross the right strand over the middle strand. Pull the middle strand to the right so that it is now the right strand. Cross the left strand over the middle strand, then pull the middle strand to the left so it is now the left strand. Continue repeating this until you have braided all the way to the end.
An alternative braided bun style is to gather your hair at your neck and start a loose braid with no hair tie. When you get to the ends, secure only two of the three strands, leaving one strand free.