I´m looking for a fic I read a while ago, but I forgot to save.
It´s about Jared/Sam being an Omega, but everybody believes he is an Alpha because he it´s big and not delicate, thats why he has never (or almost never) really selpt with an Alpha. One night he is at a bar and Alpha!Jensen/Dean walks in and right away figures out that Jared/Sam needs an strog Alpha so he picks him up and takes him home.

Found in comments!!!