The 5 Most Baffling Sex Scenes in Fanfic

Someone has made a list of the Five Most Baffling Sex Scenes in the History of Fanfiction. The list includes Frank N. Furter / Methos slash... which - get this - only comes in at third place.

Actually, I wonder how the authors cut the list down to just five scenes! Wow, all the stories I would nominate for a list like that...

How about you? What are the most baffling fanfic sex scenes you've ever read (or written)?