Nude mutual massages are not legal in most areas (nor nude body to body contact during massage service), so no place is probably going to advertise that if they do offer it from time to time. This question has been asked many times over and the answer is always the same, it is VERY rare (dispite all the porn), you can find indy girls that do it, you may find a spa here or there, that might but people who know will keep it quiet because any place offering a body slide can be closed without much effort.
There used to be a place down in Philly that had it...it was one of the iterations of Callowhill massage. It seems to disappear and then reappear every so often. But it's been a long time.
