Rotate | S + Left button | Press S then drag in the 3D View while pressing the left button. The stencil rotates about its center. |
Translate | S + Middle button | Press S then drag in the 3D View while pressing the middle button. The stencil moves in a sideways motion. |
Scale | S + Right button | Press S then drag in the 3D View while pressing the left and middle buttons. The stencil becomes larger or smaller. |
Activate/Deactivate | Q | Turns the stencil on or off. |