Setsuna's Seductions
Series: Sailor Moon
Sex factor: very high
Kink factor: bondage, questionably consensual sex
This is actually two stories, the first of which is about the end of the Silver Millenium and contains no sex at all, but simply sets up the Pluto/Tuxedo Kamen relationship which the second story carries forward in an entirely different style. Again, the sex story works best if you read it smiling.