In a normal any% run, we use the staff to get item storage, which is used for throw hovering.

Since we can't use the staff in a staff-less run (obviously), we use the Stunner ability to get item storage.

Here is a written explanation with a little more detail, since the video is uncommentated:

First: Find/Summon a melon.

Second: Pick up melon, place it on the ground, and walk over it. Don't go too far away after you put it down, because then Tak will pick it back up. You want it to stay on the ground while you are standing on top of it.

Third: Activate stunner. When you first activate stunner, Tak will launch into the air. While he's in the air, press Z + L to switch back to crazy feet. This will use 0 or 1 mana instead of the normal 20 it takes to use stunner. When you land, you will have item storage.

Remember, you need at least 20 mana to ACTIVATE stunner, but it wont necessarily cost 20 mana as long as you switch to crazy feet while in the middle of the stunner animation.