AU. Snape is a leading shrink in a mental ward of Mungo's. The ward questions his tactics - he's harsh, bullying, etc - especially when he's assigned two boys. They've both been committed for instability, post-war. Snape decides to use a new - and highly illegal - mode of treatment: alternative sex therapy. The rest of the Mungo's staff rushes to stop him - yet Snape knows the treatment is working. Snape rushes furiously to cure them before he can be stopped - but something deeper is developing between him and his patients - who happen to be Draco Malfoy and Harry Potter! Dubcon, BDSM, D/s, can be dark but with a hopeful ending.
Postwar, Darklord!Harry. Harry's cursed all Death Eaters with a compulsion hex that makes them desperate to wank off when spoken to. He then made sure that all death eaters got very public jobs. The trick is, no death eater can come without permission from the one who spoke to them. And Harry is fond of keeping Snape and Draco near him - and speaking to them a *lot*... and they’re about to the point they’ll do ANYTHING if he’ll just give them permission!
Post HBP. Snape manages to subdue Potter after killing Dumbledore, and takes Harry with him when he escapes. Voldemort, to reward Snape, has Harry bound as a slave and given to Snape. Draco, as a punishment for failing, is ALSO given to Snape. They’re kept locked up away from the other Death eaters and kept safe, so when Snape returns to Hogwarts later as Headmaster, they expect to be given their freedom. But it turns out that Snape has a dark, sadistic, and VERY perverted side. For example - He's always fantasized about fucking their virginal arses on the Head Table in front of everyone watching...
Snape's found a way to defeat Voldemort with Dark Sex Magic. It requires sex with two virgin males. Luckily for him, Draco and Harry are still virginal. Unluckily for THEM, he never told them that it required binding them to him as his sex slaves - permanently. It was a deliberate oversight on his part, for if they'd known the extent of his sadistic tastes, they'd have never agreed - would they? Whipping/caning, piercings, collar/leash/harness, humiliation, corsets, ponyplay, being rented/whored out, general kinkiness XD
AU - Draco was the best whore in the brothel; Snape was their wealthiest patron, and he ALWAYS visited Draco daily. But a new boy's been brought in, and now Snape's paying his daily visits to Harry! Jealous, Draco sets out to sabotage Harry's reputation; he just never expected to fall for him in the process. Submissive painslut!Harry, Dominant Draco/Snape.
After the war, Potter seems withdrawn, refusing to speak to anyone expect to say he needs more time. In truth, Draco has a form of imperious on him - Draco intends to make the Boy Who Lived into a first-class sex slave, and he recruits Snape to help him train Potter to the lifestyle.