"switch fragrances" button ?
I don't have one, Only button I've got when I go in there is use item
7:00?
Yup
Normally:
Offer Nyx a (steel) plug -> she refuses -> you get the idea of disciplining her -> switch fragrance button appears at 7:00
Maybe post a screenshot of your quest log
OK thank you very much. Next question, where's the plug
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