Taking as his starting point the fact that, according to Freudian theory, perversion is inherent to the human being, the author focuses upon an aspect of perversion that has been little discussed: perversion on the other side of the couch, and thereby questions of how, in psychoanalytic theoretical and clinical practice, perverted drive motions may be presented. Such a phenomenon takes various forms: actually being enacted with patients; using psychoanalytic theory as a normative rule; the individual choice of profession and so forth. To exemplify his point of view, the author presents four different expressions of sexuality in Freudian theory: genital sexuality, perverted sexuality, the sexuality of the Ideals and narcissistic sexuality. After differentiating these four sexual expressions, the author shows how each of them may generate perversion in both clinical and theoretical psychoanalysis.