Hey guys I read this fic ages ago, and it was awesome, but I forgot to bookmark it :( this is what I remember:
-it was destiel obviously
- it was multi chaptered and AU
- dean was in highschool, he met cas at a club and they hooked up.
- cas was with meg at the time but he was unhappy in the relationship
- dean goes back to school the following week and finds that cas is his new art teacher, and they start up an affair, they fall in love, cas breaks up with meg but doesn't tell dean he did for some reason, there is many issues, meg tells cas she is pregnant with his child even though its actually her bosses who she was cheating with, so cas breaks it off with dean. Dean is completely heartbroken but in the end cas finds out its not his child and him and dean eventually get back together. :D also meg is an absolute psycho.
- Sam is also in it as deans 14 yr old bro, and he falls in love with Gabriel, who's cas' brother but they can't do anything cuz Sam is epically under aged. But they are a very minor thing I'm pretty sure.

sorry if this was muddled and confusing. :/