>>11338970
If she's throwing her entire being into fulfilling how I want her to serve then that's what having a sister really helps with. I would prefer the competition be friendly and mostly cooperative, but then I take in the most messed up strays imaginable, it never truly will be.

It becomes a punishable offence when I see her lord it over her sisters. Even something like "see, assmeat? i was so eager in serving Master that throwing my body down to my knees before Him was so fast i actually knocked Master's divine body over! He gave me a headpat, i must truly be one of his most valued things!" could be construed as breaking the protocol you are all to be considered as equally worthless, although it depends heavily on tone. Any kind of scolding at all, like the classic "be good like me!", immediate punishment. Such a way of speaking should never be done by a slave, even to other things.

>>11338971
"mush" is a word that can describe a lot of slaves. They do get to be like that.

An overnighter sounds nice. Maybe something like changing something on her collar and not telling her right away. Maybe clip on a little tag or something, she might not figure out exactly what it is at first.

If you haven't given her a collar yet then perhaps her brain will never not be mush with a collaring ceremony done completely blind.