Yaoi can also be used by Western fans as a label for anime or manga-based slash fiction. Mizoguchi traces the tales back to the tanbi romances of Mori Mari. Akiko Mizoguchi describes its application to male-male stories as "misleading", but notes "it was the most commonly used term in the early s.
These terms originated in martial arts: Aleardo Zanghellini suggests that the martial arts terms have special significance to a Japanese audience, as an archetype of the gay male relationship in Japan includes same-sex love between samurai and their companions. The seme is generally older and taller,  with a stronger chin, shorter hair, smaller eyes, and a more stereotypically masculine, and "macho"  demeanour than the uke.
The seme usually pursues the uke, who often has softer, androgynous, feminine features with bigger eyes and a smaller build, and is often physically weaker than the seme.
This archetypal pairing is referenced more often in older yaoi volumes - in modern yaoi, this pairing is often seen as already encompassed by seme and uke or simply unnecessary to address. The tachi partner is conceptualized as the member of the relationship who pursues the more passive partner, the latter of whom is referred to as the neko.
Seme and uke is similar but not identical to tachi and neko because the former refers primarily to sexual roles, whereas the latter describes personality. Anal sex is a prevalent theme in yaoi, as nearly all stories feature it in some way.
The storyline where an uke is reluctant to have anal sex with a seme is considered to be similar to the reader's reluctance to have sexual contact with someone for the first time. Bara genre Although sometimes conflated with yaoi by Western commentators, gay men's manga or gei comi, also called Men's Love ML in English and bara in Japan, caters to a gay male audience rather than a female one and tends to be produced primarily by gay and bisexual male artists such as Gengoroh Tagame and serialized in gay men's magazines.
Gay men's manga is unlikely to contain scenes of "uncontrollable weeping or long introspective pauses",  and is less likely than yaoi to "build up a strong sense of character" before sex scenes occur. This emergent boys' love subgenre , while still marketed primarily to women, depicts more masculine body types and is more likely to be written by gay male authors and artists; it is also thought to attract a large crossover gay male audience.
Suzuki suggests this is because the character and reader alike are seeking to substitute the absence of unconditional maternal love with the "forbidden" all-consuming love presented in yaoi. This spiritual bond and equal partnership overcomes the male-female power hierarchy. The theme of the protagonists' victory in yaoi has been compared favourably to Western fairy tales , as the latter intends to enforce the status quo , but yaoi is "about desire" and seeks "to explore, not circumscribe, possibilities.
Mizoguchi remarked that yaoi presents a far more gay-friendly depiction of Japanese society, which she contends is a form of activism among yaoi authors. According to Hisako Miyoshi, vice editor-in-chief for Libre Publishing , while earlier yaoi focused "more on the homosexual way of life from a realistic perspective", over time the genre has become less realistic and more comedic, and the stories are "simply for entertainment".
Matt Thorn has suggested that readers of the yaoi genre, which primarily features romantic narratives, may be turned off by strong political themes such as homophobia. While Japanese society often shuns or looks down upon women who are raped in reality, the yaoi genre depicts men who are raped as still "imbued with innocence" and are typically still loved by their rapists after the act, a trope that may have originated with Kaze to Ki no Uta.
Such scenes are often a plot device used to make the uke see the seme as more than just a good friend and typically result in the uke falling in love with the seme. Other yaoi tend to depict a relationship that begins as non-consensual and evolves into a consensual relationship. However, Fusanosuke's stories are ones where the characters' relationship begins as consensual and devolves into non-consensual, often due to external societal pressures that label the character's gay relationship as deviant.
Her stories are still characterized by fantasy, yet they do brutally and realistically illustrate scenes of sexual assault between characters.