Sheldon and Amy do a scientific evaluation when she gets turned on by Zach. They determine that she's horny. He wants her to go out with Zach, but instead she tries a hand-holding experiment with Sheldon.
On Sheldon's special edition of Fun with Flags, he insists that he doesn't need Amy's help for anything. What he needs to be doing instead is trying to win her back, but hopefully he'll come to that realization soon.