If instead you choose not to swallow but to have him cum on your face, or if you want him to pull out, then follow this routine (My recommendation). Slowly take the head in your mouth, and use your hands. Tickle his penis with your fingers, running your hands all along. For about a minute, suck the head and part of the cock where his head and shaft meet. After that, slowly lick the bottom of his shaft down to his balls and passed until you get to the skin between his asshole and sac. Lick up and down from here to the head for a short while, and he's bound to cum. If that doesn't work, try sucking the side of the head for a while while either jerking or fingering him.
After a short rest, or not if you're especially horny, you both should get hard again. Now comes the real test. Go to the bathroom -- Both of you. Take a REALLY hard shit. If you want, a joint shower would be a way to be absolutely sure to be clean. Second, decide whether to be TOP or BOTTOM -- Do you want to take it in the ass, or do you want to give it? If you choose to take it, you're a bottom. Make sure he applies enough lube to your hole and his dick (or condom if you prefer) to prevent too much pain. A little is expected. As he slowly enters, tighten your crack a little. As he goes all the way in slowly, stay still. Then, as his movements become more rapid and he goes in and out, move with him. As he is slowly thrusting in, move toward him. As he pulls out, go away from him. Keep your movements aligned. If you want, noises can be a nice added effect. Whatever you do, don't just lie there, like a dead animal.
If you choose to be a TOP -- you're the man with the tool in the hole -- then things change. A condom is a good idea to prevent anything ugly (Whether something in his ass or him ... relieving himself), and lube is a must. Apply some to his ass crack, slowly fingering him to loosen him up. Apply some to either the cock or the condom. Either lay him on the bed face down, bend him over, or lay him face up with his legs spread high and his head (Face head, not dick head :-)) between his legs, and prepare to enter. Don't rush in as you would for a girl -- Go slowly. His ass, if he's a virgin, will be tight, despite everything you may think or have heard. Slowly go in if it's his first time or if he's a veteran -- Either way, don't rush. Push your head a little way in, then pull out a little but not leaving his ass.
Go back for another thrust, pushing a little further. Read his judgments -- If he's in pain, slow down or back out for a second. If he's loving it, go a little faster. Making sure to understand your partner is a must. Fuck his ass for as long as you can -- If he cum's first, keep going. If you finish before him, then jerk him off, give a bj, or let him fuck you. The choice is up to you.
There are other techniques which I personally am not into -- Such as rimming -- But you can feel free to try them. I hope this guide helped you, and I'll be writing three more -- Girl/Girl (Learned this from watching), Girl/Guy (Learned this from doing), and group (also from doing.) If you wonder how I learned all this YES, I do have sexual relations with men. I'm not gay -- I am semi-bi.
Just as a side note, you may find yourself wanting to experiment with another guy. This doesn't mean you're a full-fledged gay man. You could be SLIGHTLY bi -- I personally couldn't see myself with another guy for anything else then sex. Don't worry if that's what you feel like -- It's perfectly normal. However, my suggestion is to act on those urges and find someone to experiment with. But make sure they know that you don't want a relationship. Thanks!
