Zwicky, uninvited implicature

From A. Z., online:

"Two questions now: about the semantics of the compounds (is the gay sex alluded to specifically anal sex?), and about the development of the sexual senses (how did the compounds come to refer to male homosexuality?) The semantic question is hard to answer, because straight people in general take anal sex to be the central and defining sexual practice of gay men (so do some gay men, but in fact oral sex is the default sexual practice). So a reference to gay sex will, by implicature, suggest anal sex. There might be people for whom shirt-lifting etc. imply, rather than merely implicate, anal sex; if so, then these people wouldn’t accept shirt-lifting or shirt-lift as a reference to fellatio."

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