If you're really interested in researching the subject, you might find some interesting things at the Sexploration column at msnbc.

The guy who writes most of it explores current mainstream stuff, and also looks into lots of "fringe behavior" that you'll have to filter some.

A link that's been at the top of the page for several months, called "America Unzipped" was originally an attempt at "everything anybody wants to know (a. la. Knuth?) and might be a fairly good place to start if you're really puzzled.

John