How does Phoebe manipulate her mother?

When her mother comes in, she tells Phoebe that she know she is awake because she saw the light and ask if Phoebe has been smoking. Phoebe makes up a story about lightening one, taking one puff  and then throwing it out of the window. After brief conversation about Phoebe’s evening her mother dismisses herself with complaints of a headache. Her mother get a lot of headaches since Allie died.