You will need an 8 inch piece of fabric - sheer works well, a fabric marker or pen, scissors, a 2.25 inch metal barrette, hair elastic, needle and thread, a 7 - 7.5 inch circle to use as a pattern and optional items to decorate the finished bun cover.
1. Trace around your circular object to draw the shape on the wrong side of your fabric (I used a small plate for my object).
2. Place the hair elastic about 1/4 inch from the edge of the fabric and sew the fabric around the elastic using a blanket stitch. If you don't know how to sew a blanket stitch, instructions can be found here http://www.youtube.com/watch?v=eXkSE2TTF4s When you sew the fabric you only have to go through 1 layer, the blanket stitch will pull the fabric margin around the elastic automatically. Be careful to not sew through the elastic or it will snap when stretched.
3. Continue to blanket stitch all the way around the fabric. Tie off the thread at the end.
4. Remove the tension bar from the barrette.
5. Sew the top of the bun cover to one of the holes in the barrette. Stretch the elastic along the length of the barrette and sew the second corner in place.
6. Optional - Attach decorations to the edge of the bun cover on the barrette. Whether you decorate the cover or not you will need to replace the tension bar for the barrette to work properly. To use, pull hair back into a ponytail. Use hair or bobby pins to create the bun. Put the barrette in the hair above the bun. Pull the cover over the bun to hold securely.