Mix the shredded coconut with sugar and milk. Stir well, then cook in a pan over medium heat until the coconut mixture thickens and dries out.

Once the coconut is dry, line an ice cube tray with plastic wrap. Press the coconut mixture firmly into each mold to form compact pieces. Place the coconut pieces on a rack and chill in the refrigerator for 10 minutes. Meanwhile, chop the dark chocolate, add 1 tablespoon milk, and melt in the microwave for 30 seconds until smooth.

Pour the melted chocolate over the coconut pieces to coat them completely. Refrigerate for 5 minutes to set. Next, melt the white chocolate and transfer it to a piping bag or small plastic bag. Pipe designs on top of the chocolates, then chill for another 5 minutes before sprinkling with rainbow sprinkles.

Once the coconut chocolates are firm, place each one in a paper candy cup. Serve chilled for the best taste.