So, it's been pretty much confirmed that Kylo and Rey aren't siblings (http://matthew-daddarios.tumblr.com/post/140423384883). But I'm sure I'm not the only one who kind of wanted them to be (or at least wanted to fantasize about it for a little bit longer!).

My prompt is: Kylo and Rey are brother and sister, they're aware of this, and they have sex.