Prompt 1: Harry has always been a generous lover, but some of his past lovers haven't been and Harry has never been on the receiving end of oral sex. Severus shows him what he's been missing.
Prompt 2: Occlumency lessons have a side-effect in that Severus and Harry both start to share each other's dreams. (Can be an AU/8th year fic if you don't want to write chan). What happens when Voldie discovers this connection between his spy and the Boy who Lived?
Prompt 3: On Harry's 21st birthday he recieves a letter from Gringotts - apparently the Potters had bethrothed he and Snape shortly after Harry was born. Harry has already broken up with Ginny and he still hankers after his half-blodd prince. There's just one problem - Snape is dead, isn't he?