I think your villagers should start rioting (and raping) at -50 or -100 morale. If you beat them up after that, their morale would improve a little, but as long as their conditions are bad enough, they'll soon be back to rioting.
You'll have to ask somebody who actually did it. I never tried.
All I know, is that if you disregard their personalities and lump them all in one region, they'll start rioting soon(tm).
This is in-game now. When you're playing male MC, and female MC is down, you can use R button to get male MC to rape female MC.