In depth information what happens during Val's willing submission.
For a rough outline of each route, refer to the willing slaves route.
Note that this general outline of the route. It is not a walkthrough.
The Eager Slave
Finishing the original trip to the dungeon, the Protagonist and Val attends Dr. Tiff's, Drape's and Jane's classes, meeting with a blue loving, fire loving mage.
During Drape's class, she gets cursed and becomes unable to move her arms properly, requesting the Protagonist's assistance in getting healed.
The Protagonist enslaves her right there in the hallway before heading home and changing her personality to become Eager to Please.
Re-entering the dungeon with Sarah and Val, Sarah soon finds a note on the third floor. She happily shows it to the Protagonist, causing Val to grow confused, saying that she's acting like a puppy.
The Protagonist admits to enslaving her, causing Val to question what s/he was thinking. Sarah steps in, saying that she doesn't mind it, as she just wants the Protagonist to like her. Val, in disbelief, tells them that they should just get the hell on as she can't stand to think what went through the Protagonist's mind.
Flirting in the Library
Heading out of the dungeon, the Protagonist and whoever s/he pleases attends the first secret class. Heading over to the library, the Protagonist meets with a red haired girl with glasses, who seems to enjoy reading.
During the conversation, the Protagonist can either enslave her or simply let the conversation finish. In case of the former, the Protagonist can instantly see his/her slaves topless, while in the case of the latter, the Protagonist needs to provide a note for Julia.
Regardless of what route was chosen, the Protagonist asks to see Sarah's breasts in the library, which she willingly does. During the scene, Val walks in and questions what the hell is going on. The Protagonist is required to cast Flirt on Val during this scene, causing Val to get somewhat embarrased before hurrying off. Sarah, curiously, asks if she did something wrong.
Lake Chatter
Heading to the lake, the Protagonist stumbles on Sarah and Val talking, with Val asking if that is what the Protagonist is into. Sarah misunderstands the question, asking if the Protagonist likes straight or lesbian girls, depending on the Protagonist's gender, but Val corrects her, explaining she's asking if the Protagonist is into submissive women.
Sarah explains that it's likely - the Protagonist seems happy whenever [she] does whatever [the Protagonist] wants. The Protagonist walks up to them, asking if something's wrong, but Val apologises and hurries off instead. The Protagonist just wonders what that was all about.
Item Shop Encounter
Inside the item shop, the Protagonist once more bumps into Val, who is questioning what is wrong with herself. The Protagonist begins chatting with her, while she tries to avoid talking to him/her, but the Protagonist confronts her, causing her to quickly leave.
Val's Willing Submission
Heading home, the Protagonist changes Sarah back to her normal personality, who at this point is sick of all the tip-toeing around and brings Val forcefully back to the Protagonist's house, asking for the Protagonist to enslave Val as well. The Protagonist decides not to do so, instead wanting Val to willingly become his/her submissive lover or willing slave. Val, somewhat reluctantly, agrees to it.
Enjoying Two Slaves
Having been changed back to her Eager to Please form, she approaches the Protagonist, asking for the Protagonist to play with both of them. Val is reluctant in doing so, causing the Protagonist to reassure her and saying that she won't have to do anything she finds uncomfortable. Val is grateful and decides to join Sarah, with both of them showing their breasts for the Protagonist.
Double Titfuck
Having seen both slaves breasts at the same time, Sarah again wants to play with the Protagonist and suggests Val should join in as well.
Val is reluctant in doing so, causing the Protagonist to decide to just play with Sarah, who either sucks Dan's cock or licks Rosa's vagina.
While doing so, Val walks in on them, requesting to be allowed to join in as well, causing the Protagonist to suggest a double titfuck. Val and Sarah agree to do so.
Transformed Threesome
The Protagonist has come up with an idea: while in the Protagonist's bedroom, the Protagonist can either choose to transform into an eager to please Sarah or a normal Val. Regardless of choice, a short scene plays out in which the three women(?) are having some fun.