Ok, I just now learned a good and possibly easier way to make shading marks that aren't just made by the pencil itself.
Surprisingly, the first thing you need to perform this is.... a piece of toilet paper or a kleenex.
1.) Look for spots where shading is needed, as in by an under leg part, arm, stomach, ect.
2.) Then, just apply the pencil lead where you want it, it doesn't have to be alot, just a little bit.
3.) Then, just take a clean part of the kleenex or TP and rub in circles where the pencil lead is on your paper. Now, when you look to see what happened it may look really sloppy, but just do some clean up and trace the lines back in again. Simple as that!
Hope you all like this, maybe sometime I'll get some pictures in here to show you what I mean