I think that if I started to organize novels by their use of onomatopoeias and gitaigo my brain would leak out of my skull. I like my onomatopoeias in small doses lately but I do dabble in ahoero novels from time to time, I want to know the exact moment Rui's thick, meaty stick knocks on Tsukasa's male uterus begging to be let in and i live for nonsensical jav plots... As for recs…

You should peek Hikaru’s entire library, she was quite good at writing slut tsukasa and her use of phrases is so good (fun fact they wrote an ero dungeon trap ruikasa novel back in 2021 that was one of the inspirations for sutaore)
And also Ponde !! They’re one of my favorite og slut tsukasa writers (I’ve rec'd two of their fics before,,, i’ll maybe rec more) and they recently collaborated with Tokisame for OU3 with a small novel-comic with a far-too-jav parody title with Gyaru Tsukasa and Asocial/Secluded Rui that doesn’t completely comply with your request but I recommend nonetheless because Rui’s dirty talk is m,,nmh,gmhhhmng. maybe you’ll be interested in their Ano Ko series where Tsukasa confesses to Rui that he’s a succubus and he needs to consume Rui’s cum or else he’ll fucking die, it’s riddled with slang and fun phrases.
Slut… do you like Dantoru, anon… A recent favorite of mine is Sono [〇〇] wo Nugasete which should be 其の衣装を脱がせて but what do i know... which has Torpe getting a request to play a particularly sensual piano piece he cannot understand but desperately wants to... To expand his horizons and to study, Kaito introduces him to a male stripping club and he starts working there part-time, all while hiding this information from his dearest lover, Danchou… I love a Torpe-kun who wants to be devoured so badly ( ´ཀ` ),,,,, that summary is missing a Lot but ill make sure to add it to the rec list once i actually find that reclist. this idiot didn’t bookmark the thread ( ._. )"".

thanks for the rec btw, anon!! rui-kun purposefully messing tsukasa's counting to fuck with him is far too good... hope you’re doing okay!