Felching (sucking or eating semen out of someone's anus) is a sexual behavior about which virtually nothing has been written in the scholarly literature, despite the fact that it appears to be a not-uncommon practice among certain subpopulations of men who have sex with men (MSM). This study examined three broad research questions: (1) How common is felching? (2) How does a desire for felching relate to other HIV risk practices and risk behavior preferences? (3) What factors are associated with the desire to engage in felching? The data were from a content analysis study of one of the largest Internet websites specifically targeting MSM looking for partners for unprotected sex. A total of 1,316 profiles on the site were analyzed and selected randomly based on users' ZIP codes. Felching was mentioned as a sought-after practice in approximately one-sixth of the men's profiles. Men who wanted to find felching partners were significantly more likely than those not searching for felching partners to seek other types of risky sex, including unprotected oral and unprotected anal sex, and various enhanced risk preferences (e.g., having sex while high, multiple-partner sex, unwillingness to withdraw the penis prior to internal ejaculation). Multivariate analysis revealed several factors that were related to an interest in identifying partners online for felching, including race/ethnicity, indifference to sex partners' HIV serostatus, several sensation-seeking measures (e.g., wanting "wild" or "uninhibited" sex, self-identification as a "bug chaser"), and eroticizing ejaculatory fluids.