Deform is moving my apple

posted to: Intro to Sculpting
Trying to follow along. And when I get to the apple section... I've got a sphere. I am doing elistic reform (346px, .5 strength). When I click and hold on the far edge of a sphere, and I click and slide it inward to try to deform the apple, it does deform it, a bit, bit it also slides the entire sphere in the direction I'm dragging the mouse. Any thoughts on what I could be doing wrong here?