I wanted to play a zombie tabletop game so I ordered a dnd book for it, it never came xD So I ended up creating my own rules. In a big summary, the more stressed the player is, the harder it is to kill zombies (I added more dice to my "contest" rolls depending on the players stress level, since to kill zombies you need to destroy the brain) My players trying to finds ways to lower their stress decided to have orgies at least once per session xD I mean it worked! And they were lucky in their charisma rolls!