Some emetophiles find the act of vomiting arousing; for them, the sequence of "spasm, ejaculation, relief" in vomiting is erotically charged. Other emetophiles are aroused by seeing and/or hearing others vomit. Some desire a partner who will vomit on them, while others wish to induce vomiting in a partner, or even force them to vomit. (Wanting to be vomited on may be related to a desire to be dominated, while wanting to make someone else vomit may stem from a desire to dominate the partner - see erotic humiliation.) Of course, most emetophiles have more than one of these desires, in various combinations.
An online site theorizes, "vomiting was probably something either arousing or frightening to emetophiles at some point ... it aroused powerful emotions, and the emetophile called upon these emotions for the purpose of sexual gratification." Often emetophobia can, paradoxically, lead to emetophilia, or even a mixture of the two in which a person is afraid to vomit, but aroused by witnessing someone else vomiting.
In some cases, emetophilia is directly related to vorarephilia. The emetophile fantasizes that he or she is consumed by the person who is vomiting, and imagines him/herself as covered by the contents of the person's stomach while within the stomach of the person who is the target of their fantasy.