Dean possesed by Pan?

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I've been trying for a few days to find this fic,I have googled and looked through here  as well.

It is Dean/Sam slash and case fic.I't could be part of a series(I'm sure there was at least one story before this)not sure though.
Things I remember.
There is an old friend /ex boyfriend? of Sams ,he has a flute or pan flute that when played .....well first the guy kissed sam and he responded for a moment ,Dean saw and was not happy.Later Dean is possesed by the creature that the flute belongs to and it wants Sam who uses that to get Dean back.
Later Dean is upset with Sam for cheating even to save him .

I'm sure a lot of people would have read this and hopefully one of you can help me out.
Thanks

STORY FOUND THANKS
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