From Scientific American, an article regarding the mating habits of squid that makes one glad to be a mammal:
http://www.sciam.com/blog/60-second-science/post.cfm?id=rough-sex-at-40000-leagues-under-th-2008-12-24
"What do you do to pass on your genes to the next generation if you are really hard up, it’s too dark to see clearly and you are literally under enormous pressure? The short answer: play rough and weird."
To cross over into anthropology for a moment, I would venture to say that "rough and wierd" may describe a fair amount of activity in SL. Just an educated guess, that is.