Gay men were asked to recall two sexual encounters from the preceding year: one in which they had unprotected intercourse (“unsafe” encounter or UE) and one in which they had resisted a strong temptation to have unprotected intercourse (“safe” encounter or SE). In each case questions covered the type of partner involved, physical location, desires at each stage of the encounter, level of sexual attraction and arousal, mood, communication about desires regarding safe sex, and alcohol and drug consumption. For UE, respondents also identified self-justifications they had used when deciding to have unprotected intercourse. Type of partner distinguished between UE and SE. With this variable controlled, desires, sexual attraction, mood, knowledge of condom availability, and communication about safe sex differentiated between the encounters. Consumption of alcohol or drugs, by contrast, did not. The most common self-justification used in UE was a resolution to have intercourse without ejaculation. The first two factors that emerged from a Factor Analysis involved inferring the partner's likely antibody status from perceptible characteristics, and bargaining or special pleading. The results are discussed in terms of their application to AIDS education.