As part of the Microbicides Development Programme, we conducted formative research to explore perceptions of anal sex at a site in rural KwaZulu-Natal. We were interested in the practice of anal sex because of its potential role in HIV transmission. Eleven focus group discussions were conducted with men and women from rural areas and in a semi-urban township. Participants were asked about their knowledge of and attitudes towards anal sex, and its practice in the local population. Findings indicate that in discussion anal sex was confused with other non-traditional sexual practices like vaginal sex 'dog-style' and with oral sex. Discussion of anal sex among those who had heard about it linked it to socially marginal groups and asymmetrical power relations.