Snarry, HP/SS, Severus/Harry prompts and/or challenges.
1) Snape decides to take revenge on Harry by making advances for something his father once did, but the revenge backfires when Potter is more interested than Snape could have ever imagined.
2) Snape spreading his legs in invitation.
3) Snape is a very experienced lover, and very sure of his own attractions. When Harry finds out about this, he is very interested.
4) Harry's magic is stolen and he is turned into a squib. The only way to get his magic back is to be with a wizard who is as - or nearly as - strong as Harry himself was before the magic was stolen.
5) Harry looks at Snape in a very different way after he's seen Snape duel with Gilderoy Lockhart. Snape tries to escape Potter's attentions since he is a student and entirely too young, but once Potter turns 17 and is done with his studies, all bets are off.
6) Harry is hot and bothered but kind of clueless as to the reason why, but Snape is not.
7) Snape is dead, as far as anyone knows, but Harry finds his portrait and realizes that maybe there is a way to bring Snape back.
8) Self-depracating Snape, but Harry won't have it.
9) A fic with the title "Love Potion #9".
10) Snape is a Master at more than Potions. And, as Snape would say. "Don't be daft" when wondering what he's good at. Do I need to spell it out?
All stories should be First Time, NC-17 and no underage, since that is my preference. You may use one or more prompts/challenges in the same 'fic. Preferably on the longer side of fic. 10k or more.