Shaking it Up

An old woman goes in to a sex shop, shaking. "Sir," she says in a shaky voice, "do you sell vibrators?" "Yes, ma'am." "And are they this big around and this long?" she asks in a shaky voice. "Yes, ma'am." "And they're $22.95?" she asks in a shaky voice. "Yes, ma'am." "How do you turn them off?"