Theres 3 types of draw boosting I've found so far in this game.

Ground Boosting

Ground Boosting is where you used the lead to push your torso forward. You want to aim a little bit behind your torso when you start clicking and you can move your mouse about half-way across your arm. If you move it any more your drawing will slice in front of you stopping you.

Hover/Float Boosting

Hover Boosting is where you use the lead to push your self forward while in the air. It might be faster than normal ground boosting. This is the one I just found out about, you want to jump in the air or come off a aerial draw boost and start drawing under your torso while moving forward. Same with ground boosting, you can move your mouse half way across your arm.

Aerial Draw Boosting

Aerial Draw Boosting is where you boost your self upward in the air using your drawings. This is the hardest out of the 3 boosts. you want to a Hover boost, while jumping and moving your mouse upward/45 degrees.

examples of all 3 of theses can be seen in my latest run here