Without condom, and taking semen in the mouth or having an infection in the mouth LOW RISK
Without condom, after using mouthwash or brushing teeth LOW RISK
“Giving or getting head, headjob, cock-sucking, blowjob”
The risk in fellatio can be reduced by avoiding ejaculation of semen in the mouth and can be eliminated by using a condom.
It is also recommended that the partner giving fellatio wait 30 minutes to two hours after brushing or flossing teeth before engaging in fellatio, since brushing and flossing teeth may cause temporary bleeding of the gums.