This is not the way you're supposed to raise her corruption. Once again, we have another player who is struggling with the walkthrough.
It actually works tho. Whether you turn NTR on or off, when you switch normal wine with the cumwine in Julia's room, she drinks it with the other guy and gets corruption +1. But... Unlike Natasha you have to stay behind the door and witness it.
So it is possible to raise Julia's corruption without her licking the cum out of her mistress' pussy.
HELP... JULIA...I put the Cumwine in her her room but her corruption level is not going up; How do I monitor the room to see she consum the wine?
Switch the normal wine with the cumwine, wait untill they enter the room and sit. Wait right outside their room, skip hour by hour. When they get up and get to beds Julia's corruption will increase, but beware that the lord will be walking outside his room heading towards his bedroom. Soyou gotta be quick and head downstairs.
After doing this the first time, you dont have to wait right behind Julia's door. Only necessity is that you have to be in the same floor. You can hide in any other room in the second floor and skip hour by hour until you get notification that her corruption got increased.
I would say this should be tweaked. With Natasha when you corrupt the holy water, she gets her corruption increased when she drinks it (she does that on a daily basis) regardless you're there to witness or not (so you get daily notification that her corruption got increased). It should be same with Julia.