Remote controlled human

The red headed nurse came in holding a needle with what seemed to be a clear, transparent solution.

"Your arm, please" Nurse Jane asked

"Aren't you going to tell me what it is first?"

She gets that grin again "O, but where would the fun be in that?"

Then she leans in and whisper into you ear "I just hope the doc let's us take turns with the controls, she can't have all the fun after all"

While you try to figure what she said meant, she pulled the now empty need out of you arm and left the room, locking the door behind her.