The phenomenon of patient-therapist sexual liaisons raises important questions of technique, ethics, and theory. In this article, some aspects of both the patient's and therapist's vulnerabilities in dealing with an eroticized transference are illustrated by a case report of a patient who is a probable incest victim and who is convinced that a sexual liaison will be the inevitable outcome of her therapy. The thesis developed is that unlike other transference phenomena, the wish for sexual contact, as a repetition of past trauma, requires the analyst to rupture the area of illusion in the transference and foreclose the fantasy in favor of promoting boundary formation and repairing ego deficits. The key to introducing a parameter such as this is understanding from moment to moment the patient's participation in the play-like, illusionary qualities of the transference.