Yep, you heard correctly. Large sticks of colorful chalk allow you to become a parking-lot Picasso. Sometimes it's helpful to offer students larger-than-normal depictions of concepts to make them more understandable. For instance, you might draw a 10-foot runway (numbers, lines, and all) in some obscure portion of the parking lot. Having your student walk around this runway as a means of introducing the traffic pattern now becomes a more dramatic and memorable way of explaining the essentials of pattern operations. I knew one CFI who drew taxiways and markings along with the runway, then issued taxi instructions to his student as a means of teaching ground operations.
I once used this technique to help an instrument student understand how the head of the ADF needle always falls (moves from top to bottom) when a constant heading is held in an airplane. With the NDB drawn at some point in the parking lot, and with my outstretched hand representing the ADF needle, the student immediately saw that a constant heading (moving in any straight line) always allowed the needle to move to the tail of the airplane.
There are many ways that larger-than-normal graphic depictions can be used. The best part is, when you're done, a bit of water or a good shoe rub erases most of the evidence. You can make your mark, make your case, then erase.