Little sister is a cheer leader

[Kimmy_koi]

I have an image of a little sister cheering her brother on as he fucks his girlfriend. Not a literal cheer leader, naked in bed with her egging him on as he fucks random women. Obviously we can move into the sister getting fucked as well. I like the idea of the two having an open relationship and teasing eachother alot without having sex. I'd like our rp to go into their first time, I'll be waiting.