Clay in it's raw form is easy to mold, to shape.
You have to make sure you don't leave any bubbles. Or else when you put it in the kiln to be fired, it will pop and have cracks which will make the clay hideous, or it can destroy the clay altogether, or in the worst scenario, the clay can burst to destroy other clay in the kiln or the kiln itself.
Just thought I should share this.
Doesn't everyone who's ever been in art class know this?