Oral sex is sexual activity that involves using the mouth, lips, or tongue to stimulate a partner’s genitals or anus. It is one of the most common sexual behaviors among adults. CDC survey data from 2017-2019 found that roughly 82% of men and women aged 15 to 49 have had oral sex with an opposite-sex partner at some point in their lives. Both heterosexual and same-sex couples engage in it.
The Three Main Types
Oral sex is an umbrella term that covers several distinct acts, each with its own name:
- Fellatio involves stimulating the penis with the mouth through licking or sucking. It’s colloquially called a “blow job.”
- Cunnilingus involves using the mouth and tongue on the vulva and clitoris. It often begins with kissing the inner thighs or lower stomach before focusing on the clitoris.
- Anilingus (sometimes called “rimming”) involves oral contact with the anus.
Any of these can be performed by or on a person of any gender. They can be a standalone sexual activity or part of broader sexual contact.
How Common It Is by Age Group
Oral sex is widespread across age groups, though younger teens are less likely to have experienced it. Among 15- to 19-year-olds, about 42% of girls and 44% of boys report having had oral sex with an opposite-sex partner. By adulthood, those numbers climb to the low 80s for both men and women. These figures come from the CDC’s National Survey of Family Growth, one of the largest ongoing surveys of sexual behavior in the United States. They also only capture opposite-sex encounters, so the real prevalence including same-sex partners is likely higher.
STI Risk During Oral Sex
Oral sex carries a lower risk of sexually transmitted infections than vaginal or anal sex, but it is not risk-free. Several infections can be passed through oral contact with the genitals or anus:
- Gonorrhea is one of the more easily transmitted infections through oral sex and can cause a throat infection that often has no symptoms.
- Syphilis can be transmitted if a sore (called a chancre) comes into contact with the mouth or genitals.
- Herpes (both type 1 and type 2) spreads through skin-to-skin contact. A cold sore on the mouth can transmit herpes to a partner’s genitals during oral sex, and vice versa.
- Chlamydia can infect the throat, though this is less common than genital infection.
- HPV (human papillomavirus) can be transmitted to the mouth and throat during oral sex.
- HIV transmission through oral sex is possible but the risk is much lower than through anal or vaginal sex. Exact risk percentages are difficult to establish because most people who have oral sex also have other types of sex, making it hard to isolate the source of infection in studies.
Factors that may increase risk include open sores or cuts in the mouth, bleeding gums, and contact with ejaculate or vaginal fluids. However, no rigorous studies have confirmed exactly how much these factors raise the odds.
The HPV and Cancer Connection
HPV deserves special attention because of its link to throat cancer. The virus is thought to cause 60% to 70% of oropharyngeal cancers (cancers of the back of the throat, base of the tongue, and tonsils) in the United States. HPV spreads easily through oral sex, and most people who contract oral HPV never develop symptoms or cancer. The body clears the infection on its own in most cases. But in a small percentage of people, the virus persists and can, over many years, trigger cancerous changes in throat tissue.
HPV vaccination significantly reduces the risk of infection with the strains most likely to cause cancer. The vaccine is most effective when given before a person becomes sexually active, which is why it’s routinely recommended for preteens, but it’s approved for adults up to age 45.
How to Reduce Risk
Barrier methods are the primary way to lower STI risk during oral sex. For fellatio, an unlubricated or flavored condom placed over the penis provides a physical barrier between the mouth and skin. For cunnilingus or anilingus, a dental dam does the same job. Dental dams are thin sheets of latex or polyurethane that you lay flat over the vaginal opening or anus before oral contact.
A few practical tips for using dental dams: use a new one every time, apply water-based or silicone-based lubricant on the side facing the body to prevent tearing, and never reuse or flip one over. Avoid oil-based products like petroleum jelly, lotion, or cooking oil, which break down latex. If you don’t have a dental dam, you can make one from a condom by cutting off the tip, cutting off the base, then slicing down one side to create a flat rectangle.
Dental dams and condoms are widely available at pharmacies and sexual health clinics. Despite their effectiveness, barrier use during oral sex remains far less common than during penetrative sex, largely because many people perceive oral sex as low-risk.
Communication and Consent
Like any sexual activity, oral sex requires clear consent from both people involved. Research on how people communicate consent shows that explicit verbal check-ins become more common as sexual acts become more intimate. About 43.5% of people report using direct verbal cues to establish consent before oral sex, compared to only 22% for intimate touching. This suggests most people recognize oral sex as a distinct step that warrants a conversation, even a brief one.
Consent communication doesn’t have to be scripted or clinical. It can be as simple as asking “Is this okay?” or expressing what you’d like to do and waiting for a clear response. Nonverbal signals like nodding, pulling a partner closer, or actively positioning oneself can also indicate willingness, though verbal confirmation is more reliable and less prone to misreading. Notably, research finds that active consent communication is more common when someone is about to perform oral sex than when they’re about to receive it, likely because the person performing the act is initiating a new type of contact.