Lol I thought it was a bread stick or something that she was just tapping the bottom of the cup with, trying to knock it out of her mom's hand. :P
I think I thought it was some sort of small grappling hook that she was trying to use to drag the mug down or something.
I find it really funny that any of our possibilities would also be as equally plausible. xD She's such a troublemaker.
aw, they've gotten so big now! I love that we get to watch them grow up and learn about their personalities <3