Crossposting the comment, because I can
Couple of quickies here:
Boondock Saints - first time, awkward, confused and nervous sex between Connor and Murphy.
Constantine (movie canon, specifically) - Something, anything to do with Chaz. Actually, here's an idea - Angel!Chaz becomes John Constantine's guardian on earth. I would specifically love if the fic explores the emotions they both feel as they reconnect after the separation, considering that John has lost Chaz, and Chaz is not really the same person he was before.
Darker Than Black - Something involving Hei and November. I wrote a random smut fic for those two, where November didn't know who Hei was. I'd love to see something where they DID know.
That'll do for now XD I'll come back and add more if I think of anything.