Blend the orange and freshly squeezed orange juice on high speed in a blender until smooth.
Pour mixture into a bowl and whisk in 1/4 cup sweetened condensed milk until combined.
In a glass or stainless steel bowl, whip the feta and heavy whipping cream together until soft peaks form.
Add 2 tablespoons of sweetened condensed milk and a pinch of salt and beat until stiff peaks form.
Fold the orange and cream mixtures together until smooth.
Pour into popsicle molds. If desired, sprinkle feta chunks into each popsicle mold, poking the chunks down to distribute them throughout the mold.
Place the molds in the freezer for 1 hour before inserting the popsicle sticks inside. Freeze for at least 4 more hours.