People having sex have this desire of 'spicing up' the activity by using unusual, or simply gratifying objects or symbols that are tangible or sensed. For some unknown reasons, partners or practitioners feel the real deal of sex when they use them. Surveying back of the minds of those who hate doing it, they believe that fetishes are more of nonsense, that it cannot help at all; that these things are an abnormality or an offense to the sacredness of sex.
Alongside the discourses and what not, some weird fetishes have their scientific bases, specifically some psychological backbone. To understand more about them, it is advised to read them here.
As the father of psychoanalysis, Sigmund Freud once stated that bad or traumatic experiences in childhood pushed one to submit to kinds of fetishes.
On the other hand, products of modern research tell us that fetishes may be stimulated by the innovative brain. It's nothing about the past, but about the future pleasures they could get when incorporating 'specifications' to sexual habits. Now, there are theories explaining some fetishes we are familiar about.
It is technically called Paraphilic Infantilism. This includes infant-like activities such as dressing like a baby, breastfeeding, wearing nipples, infant bottle drinking, and the likes. This psychological phenomenon can be linked to masochism, sexual pleasure derived from fecal excretion and urination to nipples, and/or breastfeeding. Paraphilic Infantilism can be explained more clearly in women, as studies shown that those into the activity were abused when they were children.
Psychology professor Katherine Ramsland, from DeSales University, found out that role-playing as Vampires is linked to sex having pleasure with danger and death elements.
Vorarephilia, as called academically, is a sexual fantasy that is playing as if one is being eaten or is eating his/her partner.Masochism, snuff, and hypoxyphilia are its sub-fetishes.
This fetish is transsexual fantasy in nature. In simple words, fantasy with 'she-males'. It is apart from the main heterosexual-non-heterosexual issues. For example, men who subscribe to this kind is attracted for the 'exoticness' of the experience. Although this statement is more of objectifying transsexuals.
Although this is very common, feet fetish involves a non-genital part. According to studies, the brain area responsible for tactile or 'touch' perceptions transmits a message that feet has very close association with genitals.