I'm so happy to see that you are back in writing. Thank you for this new chapter!
Maybe but I imagine that in addition of making sleep, the fairy dust could be used as a local painkiller to allow guro fun on human.
Here is my suggestion for fun :
To be sure to succeed in her plan of seducing Alex, Fey want to practice her skill of pleasing female human. She already know how man work but she has no experience with woman. So Fey start to train on Alex while she is sleeping, that way, Fey can learn what make her feel good without before their first official meeting. But the only knowledge that Fey have about how lady parts work is from her owns. So when her stimulation fail to make Alex react in her fairy powder induced sleep, she do what she will do with herself in this case: use wider and deeper stimuli until there are results. Alex would have a great surprise the next morning...

And pleases, please, prety please, (if possible) don't make use wait too long for the next update.