In the story which I believe was on AO3 had Dean cursed which had is confidence taken away and could not properly defend himself...I believe. He also develops a stutter.

I do remember two scenes:

• Dean and Sam are in a library doing research. Sam goes to look for a book leaving Dean by himself. A college professor sees by himself and tries to take advantage of Dean in his current state but Sam comes to the rescue!

( Fic Ending Scene... )