Well I looked it up.
any object, activity, etc, to which one is excessively or irrationally devoted
any object, idea, etc., eliciting unquestioning reverence, respect, or devotion
Psychology . any object or nongenital part of the body that causes a habitual erotic response or fixation.
an object or bodily part whose real or fantasized presence is psychologically necessary for sexual gratification and that is an object of fixation to the extent that it may interfere with complete sexual expression
Psychiatry . the compulsive use of some object, or part of the body, as a stimulus in the course of attaining sexual gratification, as a shoe, a lock of hair, or underclothes.
Word Origin & History
fetish
1610s, fatisso, from Port. fetiço "charm, sorcery," originally feitiço "made artfully, artificial," from L. facticius "made by art," from facere "to make" (see factitious). L. facticius in Sp. has become hechizo "magic, witchcraft, sorcery." Probably introduced by Port. sailors and traders as a name for charms and talismans worshipped by the inhabitants of the Guinea coast of Africa. Popularized in anthropology by C. de Brosses' Le Culte des Dieux Fétiches (1760), which influenced the word's spelling in English (Fr. fétiche , also from the Port. word). Figurative sense of "something irrationally revered.
It seems that it's not what you do that makes it a fetish. It's how you feel and think about doing it.
So if fetishes are extra, don't act like you want it too much, and you're covered! 
