Well, if we judge modern geishas today from this forum:
http://www.immortalgeisha.com/ig_bb/viewtopic.php?f=12&t=17366 then no, the majority of them wear some form of undergarment rather than going commando. I also read the Nagajuban was traditional to wear underneath the kimono, something that they lifted their skirts to show off, not for the means of arousal per se, but to show off the design of the clothing.
Or apparently, some aspiring geishas do the following: "I wrap a live badger around my lower quarters, don my yukata, and then I roam the streets fighting crime. Kind of like Batman, except with more badgers for underwear and less dressing up in a rubber bat suit." Now
that is something I want as DLC for Kokoro with its own signature badger-fueled power blow.
Really though, I know close to nothing about the geisha and I
love the fact that we get to use this costume with Kokoro.