Mix the condensed milk and butter together in a pan and cook it over low-medium heat, stirring constantly until it has thickened and the mixture is sticking slightly to the bottom of the pan.
Spread butter on a plate for greasing and poor the mixture on it. Let it cool for 5 minutes.
Spread butter on your hands and with a teaspoon scoop some of the mixture. Put it on your hand and roll it to form a small ball.
Roll the ball on the coconut flakes until the whole surface is covered with it.