Step 1: Shaping the template
Step 2: Building the mold
To keep the popsicle sticks from sticking to the mold I covered the gluing surface with some glossy "marbled" vinyl I got at the dollar store.
I traced the template shape onto the vinyl and added a center line.
The curved tail section of the mold was built up of more pieces of foam core.
The illustraion shows a "cutaway" look of the mold. (Not the steps of construction.)