The game asked me to share feedback, and since no one has posted anything yet, I'll go ahead and be the first~
Overall opinion: I like it!
My favourite scene is the one involving the magic anti-orgasm trinket. It might be that I just haven't read enough smut yet, but this is the first time I've seen orgasms being magically suppressed in this way. Great idea!
The casualness the line "her brain registers that, at some point, the cursed trinket has found its way back onto her collar" despite its deep-running implications is quite something~
Emily's narrative... the maid with a long-standing crush on her mistress but never acted on it, thinking a commoner could never have a relationship with a noble, only to later witness her beloved mistress fawn over the newly arrived maid... It's such a a good hook, it feels like a cliché, yet I can't recall any other story with a similar plot? Another great idea!
Cynthia seems to largely respect Robin. I appreciate that the story includes moments where Cynthia assures Robin that she would release her without resentment if Robin desired to leave the arrangement, which helps lighten the story. Robin's position would feel suffocating otherwise. (Mistress, I said I did NOT want that buttplug! I, Robin, am still upset about that >_<)
Moving on to the current story's finale and further development...
There was little chance that Robin and Cynthia would marry due to societal expectations around noble marriages, yes Cynthia appeared to treat Robin like her respected girlfriend. Towards the end there were some scenes involving Robin worrying about never being able match up to Cynthia, setting up further exploration of their relationship. Perhaps they'll end up as de facto long-term partners, despite not marrying? Robin hopes so at least.
And then, (due to the "keep Cynthia to yourself" route not being written) the story takes a sharp turn by adding another maid to the mix. As much as I emphathize with Emily's situation, this development shatters any possibility for Robin to become Cynthia's equal. To add insult to injury, Cynthia starts dominating both of them even harder than before. The tone shifts from Robin being Cynthia's girlfriend, to Robin and Emily being Cynthia's playthings.
Robin herself doesn't appear to be bothered, but in the final scene, the main thing I felt was pity for Robin. This kind of route feels more suited to a story told from Cynthia's perspective than Robin's perspective. I'm personally not a fan of this route, but maybe I'm just not the target audience? ¯\_(ツ)_/¯