In medium saucepan, mix sugar and milk. There should be just enough milk to dissolve the sugar. If it is too liquidy, add more sugar. Boil on high until you get a soft ball when dropped into a cup of cold water. Add peanut butter. When it starts to fudge (pulls away from saucepan), drop by spoon onto lightly buttered wax paper on cookie sheet or flat surface. Let set and cool.