Put chocolate in a heat-proof bowl and set the bowl of chocolate in the hot water.
Stir constantly until the chocolate is melted and smooth.
Off the heat, add the corn syrup and stir with a wooden spoon until the mixture thickens and pulls away from the sides of the bowl.
Transfer the chocolate mixture onto a piece of plastic wrap and pat it into a thin disk, about 6 mm thick.
Fold the plastic wrap over the chocolate and refrigerate for at least a couple of hours or up to several weeks (check the expiration date on your chocolate).
Take the chocolate plastic out of the refrigerator.
Leave it on a counter for 30 minutes to soften slightly.
Knead the plastic with your hands to make it smooth and pliable.
Use it to make roses or roll it to a certain thickness and cut different fun shapes with it to decorate cakes and cupcakes.