That's already in the game if you use the drug system (forgot the actual name). After you get the canidium, avium, etc, there's another machine in the lab you can put that in to make stuff that alters bodies and moods like the paints in the first game. There's an injection tool you can get from a machine, and you hold the number of its slot (e.x. 5 if it's after hand, mouth, penis, butt) to select which one you want to use.
Ideas
That's already in the game if you use the drug system (forgot the actual name). After you get the canidium, avium, etc, there's another machine in the lab you can put that in to make stuff that alters bodies and moods like the paints in the first game. There's an injection tool you can get from a machine, and you hold the number of its slot (e.x. 5 if it's after hand, mouth, penis, butt) to select which one you want to use.