Broad question,,, I like way too many things surrounding those two!! I feel like brainwashing and time-machines are in two different categories altogether, if you combined those two to make it something like ‘Tsukasa travels back in time to meet Middle School Rui and Middle School Rui’s self-doubt doesn’t let him believe a word of what he says, but he seems interesting enough so he pseudo-kidnaps Tsukasa and makes him his personal toy’ I’d be incredibly down. Peak, even. I’m not adding that to the writing list but it’s very good food for thought ^q^

whatevs, onto the actual answer. I feel like having someone like Rui who makes impossible things happen makes for a nice driving force into writing those two being the worst types of freaks, just brew some insanity and have Tsukasa attempt to be the voice of reason only for him to end up being into the same things as Rui. For example, I love sticking somnophilia and exhibitionism onto Rui and sticking overstimulation and praise/degradation onto Tsukasa. Like their own little sticky golden stars for a job well done, except they’re kinks, incredible.

As for tropes, I love lots of tropes surrounding ruikasa that i love indulging in: arranged marriages/marriage for convenience, omegaverse (i am very picky about omegaverse), accidental declaration of love (basically what rui does whenever he talks to tsukasa), whatever its called when they’re both so down bad for one another but no one says anything for the sake of keeping their relationship as it is, unrequited love or one sided love (but is it?), any kind of friends with benefits, ‘everyone can see it (except them)’.

I think I’m derailing. Ruikasa exhibitionism. Ruikasa somnophilia where rui waxes poetry about a sleeping tsukasa for 40k words while rubbing his dick against tsukasa’s lips, please, thank you.