I don't make recs often but I had to for this one.
Rockabye by
thebitchtrolls.
There's no slash, but you can imagine it's lead-up to slash if you really want. I just like their relationship.
Sam can't sleep and then he can--in part with help from Dean and Kurt Vonnegut. Smarm. So. Fucking. Awesome. It makes me feel sad that this is the only fic this author has ever done for SPN.