i can tell you about the one in the middle of nasir (kink) and yoshi and doc in bed #1. its quite simple to obtain actually, on chapter 8 you just had to follow the route (like the one after ur injured and phesteur's dead). pretty sure after the breakfast, you and doc was about to spend time together at the viewing deck and yall caught razix on the act so doc bring you to the lab instead then turned on a projector. and that's pretty much it. the illustration popped up on its own. happy trying :3