A Blowjob is defined by how expertly you do it!
it's a skill that few people master. Gentle pressure or a slight milking action at the base of his cock can help to harden him up a bit. Like sword-swollowing, deep-throating takes hours of practice, to relax the gag reflex. For huge Cocks it's got to be done in a 69 position so your tongue is right on the helmit, and easily revolves repeatedly around it, in all directions. If you're working upside down on it, the curve of the Cock more comfortably slides all the way down your throat. Your lips should always cover your teeth, unless he likes for you to bite him a bit, down near the pubes. Gentle biting/pulling of only the loose skin behind the head is allowed. if you start to gag, slow down and think how smooth, warm, soft, and tasty his skin is. Cocks can be love-ly.
The thing that really drives any man wild is pointing your tongue and working it up, around, and into the hole in his dick. Whether a guy has an almost tongue-sized hole or a very little one, he'll love you tongueing it out.
Think of a Blowjob as a dance routine... you need a quiet, teasing, promising beginning. Then you must use your mouth to 'take possesion' of the whole arena. Raise the energy levels as slowly as possible, as you actually choreograph a long sequence of repititious touches, moves, twists, and shapings, so he never gets bored or loses his climax. But a few rests or slowdowns, at the right times, can prolong and intensify the climax.
When he finally can hold it no longer, just let him rip and roar. And of course you want to swallow his gift to you... it's a part of him and full of energy giving protein.
if you're lucky, he'll be able to have several more 'go's', as you gently awaken him throughout the night. The very best climaxes come at dawn.
An expert blowjob is 'the best a man can get'