livefolks

I'm not sure what you're exactly looking for, but kamerreon's collection in If Wishes Were Thestrals has a drabble that contains what you had described: http://www.fanfiction.net/s/5778243/39/If_..._Were_Thestrals and http://www.fanfiction.net/s/5778243/98/If_..._Were_Thestrals is a sequel to it.

You're in luck. I've just recently found a story where both Harry and Severus are vampires with Harry as top. The story is complete, though the epilogue has not been posted as well as a mentioned sequel. However, it's very well-written. The story is called Blood Bonds written by Pheonyx on hpfandom.net. Hope this helps you. I've also read another story of a top Harry and bottom Severus. All I remember that it was post-war and a blind Severus was stowed away by Draco where Harry eventually finds Severus. The thing Harry discovers is that he somehow, inadvertently, caused Severus to be blind. Also, those who were Death Eaters all lost a precious thing to them. In Draco's case, he could not "get it up"--he lost his ability to literally feel anything physically sexual. In the end, a key point of Harry was the key into curing Severus. Of course, this involved a potion...the whole reason why Draco kept Severus captive was to have Severus find the cure for Draco's own benefit. Hope I don't sound confusing. Also, Harry, I think, wrote poems as a living and had a goatee. If I find it, I'll link it. If not, I hope someone reads this and knows what story it is. This story is also complete. Never mind, decided to rift through my saved stories and have managed to find it. The story's on this site. It's called Jigsaw by Riffraff