In the episode "I'd Like to Start With the Cat," roughly halfway through, Charlie takes Chelsie to the coffee shop to try and get back with her. He orders a really sugary drink and sets it on the table. As they talk, the drink remains on the table for a while, but the straw moves every few times the angle changes. The straw stays in the cup, but it moves from leaning towards one side of the cup to leaning towards the other side, even though Charlie doesn't touch it.