Apparently there is a day for just about everything now-a-days. I am not sure how I stumbled across this one, but I did, much to your chagrin.
National Sex Day is June 9th for obvious reasons, it can be written as 6-9, the favorite number of more than a few folks I know. For some reason the symbol for yin yang always struck me as very sexual, reminding me of le nombre soixante neuf .
If you want to know more here is the link: National Sex Day