This is pretty easy. All you need is a shirt and some scissors. For this to work you need to be fairly small/short. Basically you need a shirt that will nicely cover your butt as is.
I think it turned out pretty cute, and you should know that the sides are slightly risque'. Plus its comfy.
Step 1: Cut Off the Sleeves.
Step 2: Cut a Strip From Each Sleeve.
Step 3: Cut the Sides Down.
Take it off and cut to that point - down from the sleeve area and in from the side.
Step 4: Tie Up the Top.
Then start at the top and use a strip to tie up the side. My original approach was just like shoelaces, but that was a little gappy when I put it on. So I overlapped the edges so that the holes lined up, and crisscrossed each end of the tie in and out. That ended up less gappy.
Either way I ended with a bow, and double knotting it first is not a bad idea.
Step 5: Make and Tie Fringe.
Cut fringe into the sides. The one at the top should be as deep as the vertical cut. Then you can make them gradually less deep if you want, as long as the bottom ones are still long enough to tie. Try to make each side even.
Cut up the sides, so the front and back are separate. Double knot each fringe. Tie them tight so that the holes inbetween are tiny.
You are done!