First, make the band for your finger. Cut a strip about 4-inches long from the hem of the shirt at the bottom, being sure to cut just around the sewn edges. Wrap this strip around the finger you'll wear your ring. Wrap the strip snugly, as the tee will stretch a bit over time and you'll want a secure fit.
Pinch where the edges meet, slide the strip from your finger and sew the edges to form a ring. Cut any excess from the strip. Don't worry how neatly you sew the edges, as this seam will be covered up.
Fold the side of the shirt over so you have four layers of the shirt. Cut out a 1 1/2 to 2-inch circle. You'll have four circles.
Sew the button on in the center of the stack of fabric circles and then sew the flower on the band at the seam.