People having a gay medical fetish use medical equipment and/or scenarios erotically.
There are many people who find medical equipment such as stethescopes, speculums or examination tables erotic. In addition, such scenarios as getting or giving a physical are well-suited to erotic or BDSM role playing.
Many people who have a medical fetish buy their role playing equipment from actual medical supply houses. Using real equipment and appropriate attire including examination gowns and doctors' attire makes a medical fantasy more realistic, which is more erotic for most fetishists. While equipment like speculums, douches and enemas deal with the vagina and anus, many people find doctors or nurses sexually appealing. Some things most people Medical role playing is very common in adult movies.