Mine are on the inside. They remain VERY sensitive that way, since they are usually so protected.

I prefer looking at, running my fingers on, and my tongue on, pussy lips that are on the inside. I've only had one g/f so far who had long enough inner pussy lips that they hung down past her outer ones. It seemed a little strange to me, and nibbling and sucking them didn't seem to do much for her. However, there were plenty of other things I *could* do for her -- such as, sucking her clit, flicking it back and forth with my tongue, licking it, sticking my tongue as far into her pussy as I could, licking the whole pink area *inside* her outer pussy lips.