We've done really weird stuff on our campaign. Last session, we had the two lines
- "Roll unarmed damage against your mother"
- "You may add two Best-Quality Parents to your gear list."
Our GM just told us we were horrible people and gave me Corruption for causing that.
But as for disturbing themes, it's never come up yet. Generally, we do horrible stuff and get Corruption. Although I expect sex occurs, considering our Khornate Renegade is happily married.
Marriage, the one thing that would have Khorne himself scared. If you imagine the Blood God, imagine what matron ends up keeping him in line.
Well Khorne kinda has a girlfriend: Valkia the Bloody. And shes cute in that homicidal daemoness way.