Note: If you are doing letters make sure you trace the backwards!
With the traced side up, use a warm iron to iron the shapes onto the wrong side of the fabric.
This step is what makes this a "rag" applique, because we are leaving an unfinished edge to enable the fabric to frey more. Cut out the shape leaving a 1/4 inch edge around the Wonder Under.
Snip along the edge to create a fringe around the edge. The closer the snips, the better the fringe!
Peel off the backing of the Wonder Under and use a warm iron to place the shapes onto your onesie. Remember, your edges will be loose, but most of the shape will now be fixed to the onesie.
Leaving the fringe loose, hand and or machine stitch around the shapes with 2 ply thread. Since I have been working on newborn sized onesies, I like to hand stitch them, but on larger ones I use my machine. The last step is to wash and dry your onesie... this is what helps the fringe get that fun "rag" look. It does not show up great in the picture, but trust me it sure looks cute!