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In short: who does and enjoys what? The manga shows us the ideal situation: the girl gets tied up and enjoys “the breathers”, attention and (to some extent) sexual pleasure. The boy enjoys the process of tying the girl up, the possibility to touch the girl and play with her a bit, the “general view”, the face expression and capturing the moments with a photo camera.
However, the real life (see Paraphilias, sexual fetishes, normality, deviations and men vs women) skews this ideal picture. Women like attention, not many women like bondage as it is without attracting someone else to their bound bodies. Men like fetish stuff and bondage and, like one popular bondage magazine used to say: “Men like to be tied up too”.
But did you see women who really enjoy tying men up?