It is a clichéd question, I know, but I'm interested to see what comes out. I may yet resort to analysing a random sampling of fanfic to see who does what to whom and how often and with what hilarious results. But I think if I did that, I'd end up doing several random samplings over time, because I have a niggling feeling the perception of who is the leading partner, sexually, in this relationship, has changed over time. Not just as in who tops, but whose idea it was to have sex in the first place and who initiates their sexual encounters at this point in time.