In series where Yaoi Fangirls are seen, at least one joke will be made that involves the yaoi fangirl's dirty imagination and at least one of the male characters. Yaoi Fangirls are somewhat infamous due to the subsets that think Het Is Ew and engage in ukefication. On the other hand, they're way easier to find in Boy's Love itself or works leaning on those themes, with the fanboy commonly used as an Audience Surrogate (in the sense that he's enjoying a genre he "shouldn't") or comparing the yaoi he reads with the romance right in front of his face. In any case, Yaoi Fanboys are vanishingly rare in fiction, and if one appears, he is most likely depicted as a crossdresser or desperately clarifying his sexuality if shown as masculine.
Male fans of yaoi are called fudanshi (loosely, "rotten man"), and tend to also read Bara.
Otaku girls who like to imagine themselves in straight relationships with fictional boys rather than shipping them with other boys tend to be called "yumejoshi" ("dreamer/delusional girl", derived from "yume shousetsu", a Japanese term for a type of Self-Insert Fic) instead to clear up the confusion. Because of how commonly this archetype is shown in Otaku media when they want to have fangirls show up, the term is often misused to mean "female Otaku". The Japanese name for Yaoi Fangirl is fujoshi (a pun that translates loosely as "rotten girl"). You can pretty much assume that all yaoi fangirls think Guy-on-Guy Is Hot, but not all women who think Guy-on-Guy Is Hot are yaoi fangirls. The main difference between a Yaoi Fangirl and Guy-on-Guy Is Hot is that the former are interested in homoromantic/homoerotic fiction and/or fanfiction and/or Shipping, whereas the latter enjoy watching men make out. A female otaku who enjoys anime and manga featuring handsome men engaged in homoerotic relationships.