I've tried every way of using the choices and no bj scene has ever happened.
All you have to do is get the blackmail route,
(in this route, you are not allowed to enter Norikos room, so if you want to collect money play other routes).
I am not going to say, all the steps, you need to choose the option Menace on second day with Noriko, to get the blackail route. (you won't get Menace route if you didnt do atleast one of few choices before)
Or maybe you haven't completed the game, did you played till you got a message on left top of the screen that the game is completed 100%? (bj scene doesn't happens immediately after first few scenes, you need to make some progress with other characters too)