First Time Performing Fellatio (blowjobs)
First of all, there are a few simple guidelines you can keep in mind when you are sucking your man's penis that will greatly improve the quality. For best results, try using at least some variety with these to make them "your own" techniques and your man will love you all the more for it:
1. Really like the penis that you're sucking. Act like you absolutely love giving him a blowjob. This is much easier if you really do. If he knows you love doing it, he'll relax and enjoy it more.
2. Don't let any air in through the back of the throat, make big vacuum.
3. Use horizontal strumming with the tongue across the base of the head on the underside of the penis to make it hard if its not already, if it is then use this to tease it.
4. Use the top of the tongue to make friction on the head, pressing it up against the roof of the mouth.
5. Watch your teeth. This seems pretty obvious but if they are pressing against the penis as you stroke, it can pretty much kill the sensation. keep them retracted and let your tongue and lips do the talking.
With these in mind, here are some more pieces of general advice for novice cock-sucking:
Deep-throating apparently requires handling the gag reflex by swallowing when it happens. In my opinion, it isn't that important. Complete enclosure isn't the strong point of oral stimulation. If that is important to you, try something else. She may be able to help by using her hands on the part of the shaft she can't enclose. The advantage of oral stimulation is the control and variety it provides, which are only available with shallow penetration anyway.
It can help if you are hungry when you do it. Never attempt going down on a guy if you've eaten a big meal recently. Make sure that you're not thirsty when you start. For some reason thirst closes up the back of your throat.
Also, concentrate on breathing through your nose deeply while doing it. (This is the only way I can hold off choking on my toothbrush every morning.)
Vary your pace of stroking up and down. He'll most likely cum once you get faster and keep going.
According to Linda Lovelace of "Deep Throat" fame, the most comfortable way to give a blow job is if your throat is straight. In order to achieve this, try laying on his chest.
She also suggests that you practice by sticking your fingers down your throat and wiggling them around until you feel the gag reflex and then ease off. Repeat until you've defeated the reflex, it'll take time she says.