If the insertive partner has HIV, using a condom during receptive anal sex can help reduce the risk of transmission by an average of 72 percent, according to the CDC. Negligible The odds of contracting HIV during oral sex are slim to none. One survey asked young MSM who cruised for sex online to list their main worries. During sex, our risk perception is replaced by love, lust, trust and intimacy. There are several ways to reduce the risk of HIV transmission from oral sex. There have been no documented cases of someone acquiring HIV through receiving cunnilingus from someone living with HIV. Most tests will become positive within 6 weeks, but it can take as long as 3 months to show up. Having a 1 in 70 chance of transmitting HIV does not mean it takes 70 exposures to the virus in order to seroconvert. Here, approximately, are the odds of getting HIV , broken down by type of exposure — and how to reduce your risk. Doctors and researchers can't be sure how many people have acquired HIV through oral sex. Differences in risk Information on how risky certain types of unprotected sex are compared to others may help people make more informed decisions about the type of sex they are having. It is clear that oral sex involves much less risk than anal or vaginal sex. Avoid swallowing pre-cum, semen, vaginal fluids, or menstrual blood Use latex or polyisoprene condoms for oral sex on a man fellatio Try the flavored ones that come without lube on them If you perform oral sex without a condom, finish up with your hand, or spit semen out rather than swallowing it Use a dental dam or cut-open condom for oral sex on a woman cunnilingus or for rimming licking the anus Dental dams are squares made from latex. So right there, the per-act risk of receptive vaginal transmission jumps from 1 out of 1, exposures to 1 out of 50 exposures, and the risk of receptive anal sex goes from 1 out of 70 to higher than 1 out of 3. These include Chlamydia, gonorrhea, HPV, herpes and syphilis. A dental dam is a thin, square piece of latex or silicone that is placed over the vagina or anus during oral sex. In late , researchers looked at all the available evidence and calculated that the risk of acquiring HIV from oral sex was very low, but that it wasn't zero.