There are several ways to prepare it for appliqué.
You could put it face down on a dryer sheet and use a small machine stitch to outline stitch it. Cut a slit in the dryer sheet and turn it right side out. The problem with this would be the delicate trunk that would not turn well.
You could cut a freezer paper shape to match the appliqué. You could iron a narrow seam allowance from around Horton and stick it to the shiny side of the freezer paper all around the edge. Hand appliqué the prepared Horton down to the background, cut a slit in the center of the background to remove the paper.
You could iron freezer paper to the back of Horton, cut out the shape with a seam allowance and use starch to fold the seam allowance back onto the paper side of the freezer paper. Set the edge well and hand stitch the Horton down to the background after carefully removing the paper.
You could cut Horton from the fabric and use narrow bias tape to outline and stitch it down to a background square.