The first installment of the Koikatsu Darkness DLC is now available, however it should be noted that in the current state that it's in right now, it's very limited.
1. Six animations are currently available during the rape scene
2. At this point in time, you can only initiate the rape scene with the school Janitor, free mode does not allow use of other male chars
3. The rape scenes are currently restricted to one new map called the Storage Room
4. The Janitor does not have any penetration animations besides fellatio, he's mostly there to hold the girls down while you rape them
5. Not all characters can be used for the darkness content currently, it seems to be limited to a few personalities
6. The DLC also adds bondage wear