Ok i finally have the time to play, and while replaying the first day (just when we enter FOG for the first time and go to the balcony) 1 scene ocurred to me, well 2 but they can be combined:
It would begin with Asuna flashing Inoda from the balcony, discretely since Kirito would walk in on her but not really notice anything, Inoda is masturbating to it but only Asuna can see him due to his abilities (some level up stuff, maybe he can make it so certain party members or just "friends" see him, etc) This could be an scene all on his own. Like maybe Asuna is masturbating because Inoda and Liz or someone are fucking is an option too.
Anyway the continuation is that Asuna invents some excuse to leave and goes to fuck Inoda, meanwhile Kirito remains in the balcony oblivious, maybe he is fixing something on it, or reminiscing, or both, etc. The camera would pan out to show us Inoda and Asuna fucking and we would switch focus between the 2. Obviously Kirito can't see either of them.