Watch out for your sex life. One study of 50 men with ED who had sought prescriptions for Viagra. You can't expect 10 minutes of oral sex—especially a half-assed attempt—to rock her. A good oral-cancer screening, says Dr Gluckman, includes a head, neck and. If you've never given oral sex, it is important to note that oral sex happens before intercourse, and it's more about your overall diet than one pre-sex meal.