First. I want to suck his cock. That is nearly almost always first; I make it clear to him that I want to suck his cock - and I want him to tell me he wants me to suck his cock. Knowing what I want he should invite me... A few times in my long cocksucking career a guy whose cock I'd like to suck (and that's really any good looking young guy in sight) has caught the vibe, or heard the word, or is just horny and outright invites me first. That's fine! (Assuming I think he's hot. If not I simply decline.) (I have occasionally declined. Usually a personality thing. I don't care to blow creeps.)
Then. I may go straight for the meat. Most often I will be polite enough to kiss his neck. If he initiates kissing I am happy to kiss and then go the neck, and the nipples, and the belly button and on down the treasure trail, lick the stick, suck the balls, tongue tickle the taint, and if things taste and smell acceptably fresh so far I will give him reason to hope there'll be some good rimming in store by bestowing a very near approach by way of a sample. Then I'm going to get to work on some industrial strength cock worshiping and my ecstasy will compete with his for a while. The more he moans the more I will swallow, rise and dive, rise, pause, dive, throat him gloriously, rise, pause, dive & throat. I will hope to be at the rise and pause part of the motion for his first spurt of ejaculation - because I want the taste and feel of it - and then dive onto his pulsing cock to feel it pump and quiver deep in my neck, and rise again for the last UUH UUH UUH thrusted gushes of wonderful hot spooge to wrap around my tongue. And then I will swallow his whole member completely and massage it with my tongue until he melts in my mouth and in my arms into a steaming puddle of satisfied young man. There is no more exhilarating, fully satisfying sensation, start to finish, than a man who wants to suck a cock completely sucking a cock that wants to be sucked.