Based on the idea that risks are knowable, calculable and preventable, dominant social scientific and health promotion discourses foster an image of individual risk control and responsibility. The presentation of the self is a moral enterprise. Accounts of unprotected sex by HIV positive people who have the potential to transmit HIV to their sexual partners can be particularly morally charged. Drawing on 73 depth qualitative interviews with HIV positive people and their sexual partners, this paper explores how the interview accounts of unprotected sex can illuminate the way in which the self is presented within the context of situated norms of risk acceptability and moral responsibility. We identify two forms of account: stories of agency; and stories of acceptability. Stories of agency tend to deny agency and abdicate individual responsibility given the circumstances, and were also a key feature of accounts in which the sexual partners of HIV positive people were placed at risk of HIV transmission. Categories of appeal included the denial of agency as a consequence of: risk calculus and condom accidents; alcohol and drug effects; powerlessness and coercion; and forces of nature. By contrast, stories of acceptability tend to justify unprotected sex as acceptable. Categories of appeal included: HIV positive concordance; and commitment in relationships. Other forms of justification included: alter responsibility; and intentional HIV transmission. We conclude that accounts of risk management are risk managed. We call for greater attention by social scientists to the way in which accounts are constructed, and in particular, to 'anti-rational' forms of explanation within accounts.