All stages of sexual perception are varieties of identification of a person with his body. What is perceived is one's own or another's subjection to or immersion in his body. … In sexual desire and its expression the blending of involuntary response with deliberate control is extremely important. … In sexual desire the involuntary responses are combined with submission to spontaneous impulses: not only one's pulse and secretions but one's actions are taken over by the body; ideally, deliberate control is needed only to guide the expression of those impulses. … But the most characteristic feature of a specifically sexual immersion in the body is its ability to fit into the complex of mutual perception. … [S]exual desire leads to spontaneous interactions with other persons, whose bodies are asserting their sovereignty in the same way, producing involuntary reactions and spontaneous impulses in them. These reactions are perceived, and the perception of them is perceived, and that perception is in turn perceived; at each step the domination of the person by his body is reinforced, and the sexual partner becomes more possessible by physical contact, penetration [for the male], and envelopment [for the female].