After you are positioned on the examination table, the radiologist (a physician specifically trained to supervise and interpret radiology examinations) or sonographer will apply a warm water-based gel to the area of the body being studied. The gel will help the transducer make secure contact with the body and eliminate air pockets between the transducer and the skin that can block the sound waves from passing into your body. The transducer is placed on the body and moved back and forth over the area of interest until the desired images are captured.
The Ancient Indian Kama Sutra , dating from the first century AD, describes oral sex,  discussing fellatio in great detail (the Kama Sutra has a chapter on auparishtaka (or oparishtaka ), "mouth congress")  and only briefly mentioning cunnilingus . However, according to the Kama Sutra, fellatio is above all a characteristic of eunuchs (or, according to other translations, of effeminate homosexuals or transwomen similar to the modern Hijra of India), who use their mouths as a substitute for female genitalia .