I received a 20 minute massage including about 3 to 5 minutes of light anal rubbing (not in far at all). Towards the end I realized how wet I was back there and surmised that she must have spit on either her finger, my anus or both. There was no direct contact except during the final manual stimulation of my penis at the end.
I've read past posts on this from Dr.'s as well as moderators that clearly say no risk - however official government sites on web indicate that there is a risk of transmitting Gonorrhoea at least.