Choosing to dance among them makes you lose a pretty substantial amount of Fae Blessing. I had 46 going in and after dancing I don't have any. I also got 6 XP in Reflexes, and I remember having gotten as much as 8 before. How much XP you get is probably dependent on how much you lose. Maybe something good happens if you have 100 energy (or some other large number) of the effect.
EDIT: 113 energy of Fae Blessing got me 11 XP in Reflexes, but no new text or anything. I lost all energy of the effect.
Watching the Fae Follower with ~115 energy of the effect didn't let me understand the patterns or do anything else special either.