This refers to the clitoris, clitoral bulbs, and inner lips or labia minora. When a woman becomes sexually aroused, her clitoris, clitoral bulbs, and inner lips become engorged with blood. These structures seem to communicate with each other as a woman is experiencing sexual excitement. It’s not as if they text, but all three are highly involved when sexual excitement is in the air. Researcher Helen O’Connell might suggest including the urethral sponge to make the axis of arousal a quartet. Others would also include the vagina and cervix as being central to women’s sexual pleasure, turning the axis of arousal into a hexagon or a sexagon.