Passion Night

Passion Night by Odiane is a plotless Harry Potter Slash Fic in which Sirius and Lupin, for no reason at all, start shagging in every permutation of their shapeshifting forms. Along the way we have ten-inch penises, gallons of "jizz", far too many vowels and (perhaps most infamously) the writer, having been reprimanded for a previous Slash Fic in which the characters didn't use lube, remembered it but thought it was an activity.

It can be read here.

""IF I GO ANY FASTER WE WILL BE AT HYPER SPEEEEEED!" Lupin shouted trying not to moan while he shouted."
 * Anatomically-Impossible Sex: The lube is just the beginning.
 * Beige Prose
 * Biggus Dickus
 * Department of Redundancy Department: How many times do we need to be reminded what form the characters are in at any given stage?
 * Faster-Than-Light Travel: Referenced.

""Its time for the passion night" Lupin said."
 * IKEA Erotica
 * The Immodest Orgasm
 * Porn Without Plot
 * Rouge Angles of Satin
 * Shapeshifting Squick
 * Slash Fic
 * Title Drop

""That was sooooo awesome" Lupin said."
 * Troll Fic: Possibly. Opinions vary on this.
 * Valley Girl: Lupin talks like one for no apparent reason.