The Brush Tease:
Almost any soft brush will work. If you don't own one, you can pick up a soft paint brush (from 1 to 2 inches wide) at any paint or hardware store. Get the softest and narrowest one you can find. If you have the money, a large sable brush (available at your local art store) is an excellent choice, though they are often expensive.
What you want to do is gently stroke the underside of his cock with the brush. Use the lightest stroke you can, especially at the beginning of your session. You can use heavier strokes as the session progresses. Pay special attention to the very sensitive area just below the tip. Press hard enough to make his cock “jump” if you can. That means he can not only feel it, but you are really getting to him.
You can keep this type of cock teasing up for as long as you like and the odds are he will never reach a point where he will be able to cum. But it will drive him crazy. Don't be shy. You can tease his nipples and other erogenous zones if they are sensitive enough.
One Finger Tease:
What you want to do here is to touch the those most sensitive parts (under the tip, especially) so that his cock reacts by “jerking” as it so often does. Have fun with it. Tickle any other part of his anatomy, too, if you like. Again, if you are doing it right, he will NOT be able to ejaculate.
The Tongue Tease:
Now you can lick and/or suck any other part of his body (don't forget his nipples) to break up the monotony, or even bite his balls if you like. But when it comes to his cock, never touch it with anything but your tongue. Always go from balls to tip as it heightens his anticipation and he won't be able to ejaculate.
There you have it, three methods of cock teasing to play with (pun intended). You can, of course, combine any of these methods during one session for a little variety. But it is fun to try them individually, perhaps in shorter sessions. They also make excellent preludes to more intense edging or ruined orgasms.
One last thing... Any of these cock teasing methods is excellent for collecting his pre-cum. Just make sure he is laying on his back. Place a small dish or saucer under the tip of his cock and watch the fun. Once he starts dripping, just keep on teasing his cock and he should keep on producing the sweet liquid. The longer you tease him, the more you can get. What you do with it when you are done is, as always, up to you.
Have fun, and happy cock teasing!