As noted previously, to be good at it you really need to enjoy it. I don’t know how you get past this if the whole procedure seems distasteful. My experience is from the gay side of this equation, so ladies, YMMV. With those caveats, and as someone who has often left guys cross-eyed and whimpering, here are my top 10 tips:
Don’t be shy. Make eye contact. As pleasurable as the physical sensation might be, for a lot of guys it’s as much of a turn-on to watch you doing it, and liking it. Keeping your head down the whole time makes you just a bobble-headed machine. Look up once in a while, watch him watching you do it. Pause to look him in the eye, hold it against your face, and lick it like a kid with a popsicle (a nice warm-up routine, that one, though also effective as a pause in the action).
Use your whole mouth. If you’re just using lips and appear to be avoiding much contact otherwise, he’ll think you really don’t want to do this at all. Let it slide along the roof of your mouth, use your tongue. Don’t just put it in; envelop it. Get it all in and instead of sucking, take a moment to work your tongue on and around it.
Mind the teeth. This goes without saying. However, once you’re good at this, and he knows you know what you’re doing and won’t scratch, you don’t need to be paranoid about a little contact with the teeth. You will of course know if you have sharper-edged ones, and where they are, and avoid those. For beginners and intermediate practitioners, though, steering clear is wise.
Test your gag reflex. Even if you haven’t learned to suppress it (and it can be learned), take it to your limit, under your own control. You’ll get better. Meanwhile, the sensation (for him) of having it hit some resistance, feeling it packed in as far as it can go, can be fantastic. Also, a little minor gagging can be yet another turn-on in itself if you can carry on as if it doesn’t really matter. (As you get better at this, you’re also going to need to pace your breathing and sync it with the back-of-the-throat action.)
Use your hands. If you can’t get it all in, use your hands to create an extension of your mouth. (I’ve had to do this myself, twice.) Play with the balls (gently). Caress the hips, run your hands up over his stomach, down along the thighs. Make it a fuller sensual experience with his dick as merely the focus, but not the exclusive focus. If you’re skilled enough (or he’s, y’know, short enough) to get it all inside comfortably, slide a hand or two around to grab his ass and pull him into you.
Vary the pace, vary the technique. It’s not a one-speed operation. You want to build to a climax, literally and figuratively. Work the top part, then the whole thing, then back off and repeat. Make it unpredictable. Don’t just bob up and down; throw in some twisting motions. Suck lightly, suck harder. Let him wonder when you’re going to get back to his favorite part again, build his anticipation. Drive him nuts.
Let him take over from time to time. If you reach a moment where he’s thrusting a little, slow down what you’re doing and let him keep doing it. Try it sometime by lying on your back and let him kneel over you (prop your head forward with a pillow for this). Getting your face gently fucked is not quite the same as giving a great blow job, but it’s a really hot variation on the basic premise. (This assumes he realizes he’s responsible not to simply pound away as you gag.)
Learn his trigger. This is critical. Guys do not all reach orgasm the same way. The sensitive areas that trigger it might be at the top, near the base, wherever. The pace and pressure with which to stimulate them effectively varies too. You need to find out what gets him off. Pay attention to his reactions. When you succeed, pay attention to what you’re doing at the time, so you can do it again next time. Or, tell him you’d be turned on by watching him jerk off, and then watch closely what he’s doing, and how, especially when he reaches orgasm. Think about how you can replicate that orally. Also, once you know how to push his button, don’t start with that. Build up to it.
At the critical moment, close the deal. If you’ve done all this, worked him into a panting frenzy and hit the right spots at the right pace, and he’s just about to blow, don’t suddenly speed up or change things. Once he’s actually into orgasm, that’s different, that’s the time to slow down, suck a little harder, finish it off warmly, deeply, savoring the moment. Show him that it’s your reward for a job well done, not just his.
Swallowing is the cherry on the cake, but if you don’t want to, if you’ve done the rest of it well, it shouldn’t matter. However – don’t make a face and spit it out like it’s toxic. Take your bow, as it were, by removing it slowly from your mouth, lick your lips with it, wipe some on your face if you don’t mind (hey, it’s all protein and good for your complexion).
I hope some of this is useful. Remember, sex is psychological. It’s not just about the sensation. You’re providing the complete experience of devoting your attention to the part of his body that has commanded a disproportionate amount of his attention since puberty. Happy sucking!