Add sugar, peanut butter, milk, butter, and cocoa powder to pot/saucepan.
Cook over medium heat stirring occasionally until mixture comes to a full boil. About 3-4 minutes.
Remove mixture from heat, and stir in oatmeal.
Using a spoon — form, and portion mixture into balls, or dollops — placing them on a plate to cool.
Let cookies cool in fridge for 1 hour, or until fully cooled/solidified. Then enjoy!