A sucked dick, in situ.
Notice the tongue, wedged between the teeth and the shaft. Likewise, also note the upper teeth, slightly raised above the shaft : both are important to avoid a very unpleasant contact with the penis, if not painful !
Observe the closed lips, tightly sealed around the dick. Tight fitting lips create a friction ring around the shaft. The sliding of that tight ring along the shaft is important to satisfy the man.
What is less clear in that drawing is the tongue’s role. The deeper portion of the tongue is used to create a sucking effect around the frenulum (the back of the cock’s head). Often, the tongue will wrap around the under part of the shaft, forming a ridge. The tongue being granular and a little rough, forms a warm, wet, and delicately scraping surface that drives the dick crazy.
Also not very clear here is the role of the soft palate (forming the hind portion of the mouth’s roof). Contrary to what’s shown here, the soft palate hangs low and will rub against the cock’s head. The palate and soft palate being textured, the to-and-fro movement of the penis in the mouth will cause the cock’s head to rub against the palate, providing yet another titillating texture.
More advanced suckers will have better control on their gag reflex and will allow the cock-head past the uvula (a fleshy extension at the back of the soft palate that hangs above the throat), into the pharynx. The entrance to the pharynx is rather narrow, with the tonsillar pillars on easy side offering some resistance as the glans’ corona rubs against them as it slides in and out of the pharynx. This adds yet another texture…
With all the stimulations it offers, one can grasp why men are so fond of correctly performed fellatios !
A properly handled fellatio may easily result in a brutal flooding of your mouth with cum. Brutal because the orgasmic man tends to push his dick forward (hence deeper in your mouth in this case) when ejaculating. Brutal because the orgasmic dick becomes maximally hard and big. And brutal because the initial spurts of semen are very powerful to the point of triggering the gag reflex for the uninitiated.
Despite all this relative brutality, feeling a man cum inside your mouth is a strong experience. Feeling the man’s muscular contractions and sudden tension. Hearing the man’s moans. Seeing the man’s tensed face. Feeling the rhythmic throbbing of the penis inside your mouth. Feeling the jizz hitting the back of your mouth. Knowing you made him happy…