Well, I just posted earlier about looking for a wee!chesters fic.  I had thought that both scenes I was thinking about were in the same fic.  But only one of the scenes was in it.  So now that means I am searching for another one.

In the scene Sam tags along with Dean and some friends of his from school to the movies.  When Dean isn't around the 'friends' are mean to Sam and I think they might even put him in a dumpster.  I think Dean later takes Sammy to the carnival.

Thanks for any help!

ETA: Found in comments by mollieclarke.