Paraphilia (previously known as sexual perversion and sexual deviation) is the experience of intense sexual arousal to atypical objects, situations, fantasies, behaviors, or individuals. Such attraction may be labeled sexual fetishism. No consensus has been found for any precise border between unusual sexual interests and paraphilic ones. There is debate over which, if any, of the paraphilias should be listed in diagnostic manuals, such as the "Diagnostic and Statistical Manual of Mental Disorders" (DSM) or the International Classification of Diseases (ICD).

The number and taxonomy of paraphilia is under debate; one source lists as many as 549 types of paraphilia. The DSM-5 has specific listings for eight paraphilic disorders. Several sub-classifications of the paraphilias have been proposed, and some argue that a fully dimensional, spectrum or complaint-oriented approach would better reflect the evidence.

Klismaphilia (or "klysmaphilia"), from the Greek words ("enema", from , "deluge, flood") and ("(fraternal) love"), is a paraphilia involving enjoyment of, and sexual arousal from, enemas.

The term "klismaphilia" was coined in 1973 by Dr. Joanne Denko, an early investigator in this field, to describe the activities of some of her patients. A person with klismaphilia is a "klismaphile" or "klismaphiliac".

The DSM-5 adds a distinction between "paraphilias" and "paraphilic disorders", stating that paraphilias do not require or justify psychiatric treatment in themselves, and defining "paraphilic disorder" as "a paraphilia that is currently causing distress or impairment to the individual or a paraphilia whose satisfaction has entailed personal harm, or risk of harm, to others".

The DSM-5 Paraphilias Subworkgroup reached a "consensus that paraphilias are not "ipso facto" psychiatric disorders", and proposed "that the DSM-V make a distinction between "paraphilias" and paraphilic "disorders". [...] One would "ascertain" a paraphilia (according to the nature of the urges, fantasies, or behaviors) but "diagnose" a paraphilic disorder (on the basis of distress and impairment). In this conception, having a paraphilia would be a necessary but not a sufficient condition for having a paraphilic disorder." The 'Rationale' page of any paraphilia in the electronic DSM-5 draft continues: "This approach leaves intact the distinction between normative and non-normative sexual behavior, which could be important to researchers, but without automatically labeling non-normative sexual behavior as psychopathological. It also eliminates certain logical absurdities in the DSM-IV-TR. In that version, for example, a man cannot be classified as a transvestite—however much he cross-dresses and however sexually exciting that is to him—unless he is unhappy about this activity or impaired by it. This change in viewpoint would be reflected in the diagnostic criteria sets by the addition of the word "Disorder" to all the paraphilias. Thus, Sexual Sadism would become Sexual Sadism Disorder; Sexual Masochism would become Sexual Masochism Disorder, and so on."

Bioethics professor Alice Dreger interpreted these changes as "a subtle way of saying sexual kinks are basically okay – so okay, the sub-work group doesn’t actually bother to define paraphilia. But a paraphilic disorder is defined: that’s when an atypical sexual interest causes distress or impairment to the individual or harm to others." Interviewed by Dreger, Ray Blanchard, the Chair of the Paraphilias Sub-Work Group, explained: "We tried to go as far as we could in depathologizing mild and harmless paraphilias, while recognizing that severe paraphilias that distress or impair people or cause them to do harm to others are validly regarded as disorders."

Charles Allen Moser pointed out that this change is not really substantive as DSM-IV already acknowledged a difference between paraphilias and non-pathological but unusual sexual interests, a distinction that is virtually identical to what is being proposed for DSM-5, and it is a distinction that, in practice, has often been ignored. Linguist Andrew Clinton Hinderliter argued that "Including some sexual interests—but not others—in the DSM creates a fundamental asymmetry and communicates a negative value judgment against the sexual interests included," and leaves the paraphilias in a situation similar to ego-dystonic homosexuality, which was removed from the DSM because it was realized not to be a mental disorder.

The DSM-5 acknowledges that many dozens of paraphilias exist, but only has specific listings for eight that are forensically important and relatively common. These are voyeuristic disorder, exhibitionistic disorder, frotteuristic disorder, sexual masochism disorder, sexual sadism disorder, pedophilic disorder, fetishistic disorder, and transvestic disorder. Other paraphilias can be diagnosed under the Other Specified Paraphilic Disorder or Unspecified Paraphilic Disorder listings, if accompanied by distress or impairment.