I'm an erotic romance author in my late twenties, and a HUGE fan of HP fanfiction, and fanfiction in general. It's where I got my truest start in writing, and really, in having an online community.
My favorite fandoms are HP, Power Rangers, and Gundam Wing. I've dabbled in some others, but these are the ones that bring me back time and again.
For HP fandom, my pairings of choice:
And some threesomes featuring some of those parings, plus appearances by Lucius and Remus.