Force host does not work apparently. 3 games with Force Host ticked, and never got host.
Pretty sure lilli forgot to add force host code. Either way when you force host you press it in menu and it works by changing the minimum players needed to start the game witch will load you into a game by yourself as host. Then people will join. There are a lot of others tools that have Force Host that are public on MPGH and other hacking forums.