Combine the sugar, flour and cocoa in a medium size sauce pan. Add milk in slowly, wisking to combine over medium heat.
Heat until the mixture thickens (about 2-4 minutes over medium heat) while stirring constantly.
Pour mixture into a measuring cup or bowl with a spout to make it easier to pour into the popsicle mold. I like to use a funnel so I don't make such a big mess. Pour into the popsicle mold up to designated fill line.
This makes 4-6 fudgesicles depending on how much you taste along the way ;) Freeze overnight.
Run the outside of the popsicle mold under luke warm water for about 15-30 seconds to loosen the fudgesicles for easy release.