For a few days, this is what she was doing after she had a bottle. I wish the video was clearer, but it was bedtime so the room was only dimly lit and her white noise was already turned on.
I have no idea how she made the connection that this action was even possible let alone as funny as we found it. When she drinks a bottle, she cups her tongue like a U around the bottle nipple while she's sucking. This is something that breastfed babies do, so it seems that she still has that skill even though we haven't really nursed since July.