I never read it. I just remember the summary. something about sirius' and severus' last year and Sirius fool snape into a relationship and makes him believe it, but in the end(it implies) that he hurt Severus deeply. If I find the fic I'll put the link up and I can't and I'm hoping someone read it. I saw it on FF.net, but now I can't find it and ff.net's search engine can be such a pain.
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lol...I always seem to stumble across fics I'm looking for after I've posted on here for help. Anyway, I'm pretty sure this is it if anyone wants to read it :http://www.fanfiction.net/s/1675910/1/Find_You
Ignore the above summary on it. I was completely off. Just seems to be about Sirius playing a prank on snape and not understand the serious consequences to performing unknown spells. Pretty decent.