Autoerotic asphyxia is the practice of self-inducing cerebral anoxia, usually by hanging, strangulation, or suffocation, during masturbation. This study investigated the relationships between: asphyxiators' ages; two paraphilias commonly accompanying autoerotic asphyxia, bondage and transvestism; and various other types of simultaneous sexual behaviour. Subjects were two concurrent series totalling 117 males aged 10-56 who died accidentally during autoerotic asphyxial activities. Data concerning sexual paraphernalia at the scene of death or among the deceased's effects were extracted from coronors' files using standardised protocols. Anal self-stimulation with dildos, etc., and self-observation with mirrors or cameras were correlated with transvestism. Older asphyxiators were more likely to have been simultaneously engaged in bondage or transvestism, suggesting elaboration of the masturbatory ritual over time. The greatest degree of transvestism was associated with intermediate rather than high levels of bondage, suggesting that response competition from bondage may limit asphyxiators' involvement in a third paraphilia like transvestism.