Fellatio
Fellatio refers to the oral stimulation of the penis using the mouth, lips, and tongue. The term comes from Latin and is used mainly in medical, sexual, and technical contexts. Colloquial terms such as blowjob are common, though they may sound casual or vulgar depending on the setting.
Fellatio can be pleasurable for both partners, but it requires consent and consideration. Hygiene, communication, and a gentle approach are important, especially with regard to teeth, pressure, and gag reflex. Not everyone enjoys this practice, so boundaries and preferences should be clarified in advance.