Pull Someone's Leg Meaning

(idiomatic) To tease someone; to lead someone on; to goad someone into overreacting. It usually implies teasing or goading by jokingly lying.

Example: 1934, Rex Stout, Fer-de-Lance, 1992 Bantam edition, ISBN 0553278193, page 111:
  I hadn't pulled Mrs. Barstow's leg for any of that stuff, she had just handed it to me on a platter, and that wasn't my fault.