pulling my chain

Somthing or someone who is bullshitting you into doing or thinking somothing. Lying to you

Grandson: "i went to church last sunday grandpa "
Grandpa: " i didnt see you there are you pulling my chain!

pull my chain

pull my chain/pulling my chain means that someone thinks your lying about something or they are scared that you are lying about something.

“Are you sure your not just pulling my chain?”
“I promise i’m not.”
“Ok, please don’t pull my chain.”