Although it is not properly a synonym or a slang word for homosexual man, we include the term because of the peculiarity of its origin. Virer sa cuti means to change political opinion and in the context in which we speak, it means to become homosexual. Although in recent years it is also used to talk about someone who has lost his virginity.
We find a similar expression in Spanish, Cambiar de acera (Change sidewalks), as well as in Italian, Saltare il fosso (jump the moat), the latter more in the sense of taking a transcendental decision or in this context, coming out of the closet.
Returning to the French term, Virer sa cuti has its origin in the obligation imposed by the 50s French government, to vaccinate all children and adolescents against tuberculosis. To check the effectiveness of the immunization each year tuberculin was injected into the patients. If the next day an allergic reaction was observed, or cuti-réaction on the skin, the patient was well immunized. This allergic reaction on the skin, that substantial change of appearance, was named Virer sa cuti and from there, its different meanings spread. First, to the fact of radically changing political ideas, and later to also refer to those men who switch from heterosexuals to homosexuals.