I don't think I ever got the same option, although my game might be bugged. I've tried to find those rumored scenes multiple times, and will try again with this new knowledge, but still kind of thinking my game is bugged. Does anyone have a save before the choice? Thanks in advance.
Edit: Yeah, still having no luck finding it at the second spanking in his room. I did try a restart right from Chapter 6, but that didn't seem to help either.
It's right after the first time you use the whip on her, the quest log should say.
"I should order Liza to clean the kitchen! (noon)"
Don't do that just yet! go to sleep until the next morning. Then go to the kitchen and catch Liza there, you'll get the morning spanking scene again.
Now there's two options that will be displayed on screen.
"Auto spanking"
and
"Full spanking"
Choose the "full" option and do the spanking. You must spank her until the "Liza break" bar is empty, then you will get the option to "continue the spanking"
Continue spanking two times and she will pass out. Pick "take advantage of the situation" and then "take off her panties", when Anne show up pick "manic rapist mode" to get the scene.
-----------------------------------------------------------------------------------------------------------------------
*Just found out that you can get the scene even earlier than after the first time whipping of Liza.
When you start the blackmail route, Liza will try and kill you in the bathroom with a knife.
The next morning you will talk to her in the kitchen and the new photo session quest will be started.
Liza will refuse to participate in the photoshoot and the quest log will tell you to talk to Anne in her bedroom (noon/afternoon?)
Don't talk to Anne just yet and go to sleep until the next morning.
Liza will be in the kitchen, go talk to her and you can get the morning spanking scene here.