A few first violin girls from my orchestra inquired me on the proper way to do a blow job. As someone who appreciates this fine art, I did some calculations, did some fieldwork and went through my lab notes and this manual is the result. The following observations are of course very subjective, are from my own experiences and preferences and might not be entirely compatible with your applications. Apologies if this manual is hetero normative and cis male centric, although some principles are possibly universal and probably also apply to cunnilingus and to other sexual and counter sexual topologies.
1. Lubrication. Although dry oral or manual stimulation of the penis can be pleasant for short periods of time, in general some sort of fluid lubrication is preferred. This can be sputum, pre seminal fluid, perspiration or a personal lubricant (mostly water based hydrogel or silicon based gels). We like it smooth. When there is no lubrication at all, or when the viscosity of the lubricant is too high (optimal viscosity is probably between 0.070 and .081 Pa·s at 293 Kelvin), the friction between mouth and penis gets very high, making it painful and increasing temperature to non optimal levels. In the worst case, structural integrity of the epidermis of the penis is compromised. Optimal friction should be less than 0.04 µs. Of course when friction is too low (< 0.01 µs) the tactile perception of the fellatio will be non significant.
2. Pace. Medical history shows that very often, women (and men) perform the fellatio very quickly as possible and try to finish it as quickly as possible. Pace is very important: like in music, phrasing and buildup are very important. If the fellatio is done from a recreational perspective, there should be no rush. A slow buildup, with long periods of very slow phrases is very pleasant. For some short phrases one could do an allargando, followed by meno mosso. In general, faster tempi should be kept for the finale, although short bursts of medium tempo can be applied. The preferred tempo envelope is very personal and differs per interpretation. To give an example of a possible phrasing and tempo envelope: starting with largo (mm around 40), some short phrases (4 bars in 4/4 measure) in larghetto, menno mosso to largo, larger phrases in andante (mm 76, 16 bars) to adagio, then back to largo with some larghetto (4 bar) phrases. After a few of these cycles, stringendo, accelerando to andante, allegretto, then stretto exponentially via allegretto and presto to the finale. After the finale, tempo should be very slow again, slower than Lento (mm < 30) and rallantando to zero. Be aware that tempo is very personal, what works for one person on the receiving end, might not work for another. The fellatist should allow plenty of rubato. This also depends on the amount of friction. When the friction is high (> 0.12 µs) higher tempos than andante will be painful. Also, for reaching the finale, it is often quite difficult for the receiving end to reach climax if the receiving subject can not determine the tempo himself. In many cases, that is the main reason why a lot of the fellated prefer to reach climax by themselves, or by determining the tempo by keeping the fellatist's head static and moving the pelvis in the by the fellated preferred frequency of the oscillation.
3. Distribution of attention. Some fellatists tend to concentrate the application of the labia on the corpus of the penis but it is good to divide the attention along the whole of genitals. Some attention on the radix of the penis, the glans, the frenulum, the corona etc is appreciated. Be aware that the glans, especially the corona, can be very sensitive, especially among males who have no prepuptium due to circumcision. Also some attention to the scrotum (con tenerezza) is very much appreciated.
4. Distribution of force. Many women use only their (oral) labia for fellating, but the use of the lingua and hands is also very much appreciated. Properly combining all these in a creative and balanced way is one of the things that distinguishes the beginners from the advanced fellatio enthusiasts. It is however natural to have some emphasis on the use of the labia and then Gauss distributed on the radix of the penis.
5. Cultural and personal insignificance of reaching climax. Although reaching climax through fellatio is extremely pleasant, it is not the most important part of the experience. The fellated can choose not to reach climax at all, or might interrupt the procedure and choose another variation from the sexual repertoire, for example, reciprocal oral simulation (cunnilingus) or penetration. Some fellated do not wish to come during fellatio, because reaching climax in the oral cavity can be something not every fellatist appreciates, or is of such an intimacy that either participant wish to refrain from it, either forever, or until a more intimate rapport is established between the participants. In some cases, ejaculation on the face is a preferred modus operandi for some, while in other cases, one would pefer ejaculation during penetration. The swallowing of the semen is another level of intimacy and is an acquired taste.
6. Duration. Receiving fellatio is always appreciated if done by someone who is motivated and at least moderately skilled. If one of the persons involved lacks enthusiasm, then one should abstain rather than perform the task half heartedly. Very often, the potential fellatist does not mind or actually enjoys the activity, but may not wish to persue the activity for a very long time, or needs a break because of fatigue or muscular strain, or does not want to experience ejaculation in the oral cavity. It is very important that the parties involved know about each other's fellatio policy and estabelish a mutual fellatio protocol. In general, even a short moment of fellatio is appreciated. Taking breaks when doing fellatio when needed is also recomended. In some cases, a proper warming up, with stretching of the jaw muscles might be wise before starting a very long fellatio session. Like any other sport, a cooling down afterwards, with stretching and a protein shake help to prevent injury. Varying with other sexual or intimate activities, or not choosing the fellatio platform for ejaculation is also completely acceptable.
Above all: ask for feedback, and practice, practice, practice. The 10000 hours rule is equally applicable for this art. If you wish to become a fellatio virtuoso, there is no other way around it. And if you need help practicing and need feedback and coaching, I might be able to help. For science!