Dr. Joanne Denko coined the work klismaphilia to describe the practices of some of her patients who enjoyed the use of enemas as a sexual stimulant. Since then questions occasionally appear in the professional literature asking about the relationship between enemas and sexual pleasure. This paper considers some of the physiological aspects of the human sexual apparatus that relate to anal sensitivity and explores why klismaphilia can be sexually grafifying. The paper starts with a discussion of the physiological basis for anal sensitivity and anal masturbation in both the human male and the human female. The paper then goes on to relate all this to the sexual sensations received from an enema, and discusses the similarities and differences between all these types of stimulation. Some of the psychological aspects of klismaphilia are also considered in relationship to the physiology involved. The paper concludes with a brief discussion of masked anal masturbation among the population at large. A comprehensive list of references from the literature is given to support these findings.