Then I cut out the shape.
I cut out a rough outline around the shape of the whale, and then things got messy.
Then, still feeling the shirt needed a little something, I added a spray in the shape of a heart, using the same paper-backed sewing technique as last time. This was a total failure (when will I learn!?), and I ended up having to hand-sew the heart on because there were so many gaps in my machine-sewn seam.
If I were to do this project again, I would sew the two pieces of fabric together first before doing any cutting, which I hope would prevent the numerous gaps and wrinkles I kept accidentally sewing into the seam.