I was surprised when I saw the risks for oral sex on this chart - http://www.sfcityclinic.org/stdbasics/stdchart.asp but they may be taking into consideration other factors like having a sore in your mouth.
They are leaving out some other nasty things like strep or maybe EBV which are also possible.
I am curious if using something like Listerine Antiseptic immediately after mitigates the risk at all if it is NQBS - or after DATY.