How to make them poop?

Hello. I made a mod (HungerLK) that make submariners hungry over time. Mod works fine, i guess, but i want to extend it. I already understand how to add new feature, "PoopinG", but there is one thing that bother me. I play mostly alone, so all things that i try to add in the game, should work with bots. Now bots can have a snack on they own when hungry, and even feed each other. But i don't understand how to force them to go and take a poop when they full.
I noticed one thing, when bots are idle, they can find nearest chair and take a seat. My idea is simple, to remove "want to take a dump" status, you need to sit on "special" chair. So i need to somehow force bots to seat, when certain condition met.
My quiestion is : Where in game code, i could find parameters that change bots behavior?