Heterosexual anal intercourse is the most efficient sexual vector for HIV transmission, yet little is known about this particular sexual behaviour. Recent findings have highlighted anal sex as a significant but neglected source of HIV infection. This paper serves as a discursive exploration into the under-discussed topic of heterosexual anal sex and pervading penile-vaginal heteronormativity. To understand the origins and character of the seemingly universal ambivalence towards heterosexual anal intercourse I attempt to situate it historically. There is general ignorance concerning the prevalence of this sexual behaviour, but there exist deep-seated taboos and undertones of immorality and abnormality associated with it. All these factors play a part in individual sexual decision making; an attempt is made at exploring the motivations and personal choices that culminate in an act of heterosexual anal intercourse. These perceptions of heterosexual anal sex have shaped responses to the global HIV epidemic and influenced the design and content of safe sex education, behavioural interventions and clinical services.