Fellatio is an oral sex act involving the use of the mouth or throat performed by a person on the penis of another person. Oral stimulation of the scrotum may also.
Do not have oral sex if either of you has sores in or around your mouth, vagina, penis or anus, or if the person giving oral sex has bleeding.
You can catch syphilis by coming into direct contact with a syphilis sore during vaginal, anal or oral sex. Sores may be on your partner's penis.