[...] I keep seeing is sentences like "fucking her sex", "her wet sex", instead of vagina, pussy, etc.
"Vagina" ? It's a porn dialog, not a medical publication.
Note that I don't say this against you, but because the problem is more cultural (in a large meaning of the word), when not educational (still large meaning), than effectively a question of translation.
Hearing a girl say, "look how wet is my vagina", would turn me off way more than hearing her say, "look how wet my sex is". The first one being, for me, way too anatomical than anything else ; in addition to be only partly incorrect. This while hearing her say, to take another word, "look how wet is my fanny", would led me to answer something along, "excuse-me, but haven't your mom told you that you've to keep your panties in front of adults ?"
While it's true that few people effectively use the word "sex" to talk about their genitalia, whatever the language, it stay the word for it. And a word that have an international meaning. Except perhaps "pussy", that seem to be international, any other words used are either anatomical, or analogies. Therefore, either they feel to clean, or end lost in translation ; a translation that happen twice, since it's not just the author that isn't necessarily a fluent English speaker.
