Yes,
you definitely need a pencil, preferably, with a nice eraser and, of
course, nicely sharpened but to keep them sharp are these neat little
things called "Sav-a-Point" which are like pen covers only you can put
them on your pencils and chalk pencils to keep the points from breaking
or smearing on other things. You can even put them over the tip of your
spring action scissors which is a very, very wise thing to do since the
point of those are so sharp.
I love these and use them as much as I can.