What happens to throw WonderBoy and Anne-Marie off their rhythm, after their first successful scene together?

After one scene , WonderBoy tried “the mouth mash” with Anne-Marie, but she injured him to protect herself (157). He proposes to Anne-Marie, not as Ferdinand to Miranda, but as WonderBoy to Anne-Marie. She rebuffs his proposition, and this sends him into a sulk and a series of “lackluster” performances (157).