>>83841352>I temporarily filled it with a sad emotional beat where they realize they've grown apartYou should build on this, perhaps some of Bae's motivation to get with him is not entirely lust ("If we have sex we can fix our relationship and be close like we were when we were younger again"). This distance also reduces how much he'd be against the idea- if he hasn't seen his sis in years or sees her only a few times a year, there's less of a "this is a family member" in his mind than "hehe boobie" when he walks in on her naked.
I think it will be better if you have a slower buildup over a few days. Delaying when they "cross the line", but building to it as it seems inevitable with each incident but still in a "are we really doing this?" moment makes that final impact stronger. Since it looks like you have her initiating, what causes him to give in? Is he single and lonely? Does he also feel bad about their relationship and see this as a crutch to repair it? Or his lust gets the better of him?
You can of course ignore all this and just make it a straightforward smut fic, but I think if you touch on these even a little it'll make the moment they finally do it all the more impactful.
