Links have been reported between oral sex and oral cancer with human papillomavirus (HPV)-infected people. In 2005, a research study at Malmö University's Faculty of Odontology suggested that performing unprotected oral sex on a person infected with HPV might increase the risk of oral cancer. The study found that 36 percent of the cancer patients had HPV compared to only 1 percent of the healthy control group.
Nancy Friday's book, Men in Love – Men's Sexual Fantasies: The Triumph of Love over Rage, suggests that swallowing semen is high on a man's intimacy scale. The man receiving fellatio receives direct sexual stimulation, while his partner may derive satisfaction from giving him pleasure. Giving and receiving fellatio may happen simultaneously in sex positions like 69 and daisy chain.