Ugh im glad youre not writing the story lol
Jamie's first time being a foursome really sounds like the worst and most shitty idea ever sorry.
And Jamie and Tsukkiko both stated the reason why CJ and she didnt had sex yet already it supposedly will be the/a "big bang", whatever that means in detail but the possible impact is impalpable. They arent prepared for that yet.
I think it will happen in chapter 50 as the avn is supposedly changing a lot after that.