Well, use your hand as well as your mouth and tongue.
If you are right-handed, get your right hand round the base of his shaft.
Put him in your mouth and let him go stiff if he's not already.
There's a spot a bit under his glans that is a bit softer than the rest of him. Your tongue will easily feel this.
Start to move your tongue, layed flat, and your hand in tandem.
Keep the same amount of pressure and don't worry about the spit that's going to build up and go down your hand!
Put just a wee bit more pressure on that soft spot under his glans with your tongue as you go past it.
Remember, your hand and mouth are moving together. Your hand goes up as your mouth does.
Relax your lower jaw! That's why there's going to be some saliva/spit there.
When you feel him start to go seriously hard, DON'T LET UP! Keep the SAME pressure and tongue movement.
Don't take him out and flick his glans round with your tongue like in pornos.
He'll start to push harder in your mouth.
Exhale and let the lower jaw go even more slack.
Get him WAY to the back of your palette.
And swallow, swallow, swallow.
There, was that nasty enough?
Practice makes perfect.
Do it with him sitting in a chair watching you and have him coach you through it.
Lots.