If you are asking how to give oral to a woman then you have either never done oral sex (cunnilingus) or you have tried to give oral to a woman but did not get the desired results, which are screaming orgasms or even multiple orgasms.
There are a few golden rules to remember about giving a woman oral.
1. Be clean shaven as there is nothing more off putting as a guy who can't even be bothered to make the effort to shave before he licks a womans most delicate parts.
2. Be gentle, again it is such a huge turn off to a woman if you just get on down and start licking her. So take a chill pill and relax, explore her gently.
3. Don't go straight for the money shot, leave the clitoris alone until you have got her fully aroused because if you go for it too soon again this will turn her off.
4. Know what you are doing before you give oral to a woman by getting hold of a cunnilingus guide such as Lick By Lick which will take you from a beginner at oral to a fully fledged oral expert who can make any woman orgasm almost instantly with your tongue.