It's now time to put the panda aside and work on the pillow...
Measure the dimensions of your panda's torso and add half an inch, all around, for seam allowance.
We now need our piece of cotton/calico.
You can either do this the regular way and cut out two rectangles and sew them together, leaving a gap of approximately 2" for turning. Or you could fold the cotton in half, chalk your dimensions on the fabric (as we did with the limbs and ears) and sew on the drawn line, also leaving a 2" gap for turning. Either way will work fine - just pick the one you're most comfortable with.