During fellatio, the person giving the hummer can wrap their lips around the receiver’s penis or balls. As the vibrations are the most intense at the opening of the mouth, humming against the sensitive head of the penis can be very pleasurable. When performing a hummer on a female, the giver may hum against the clitoris and any other part of the female genitals.
A hummer may be used as an alternative to traditional oral sex or as a component to add variety during the usual licking and sucking.