Please, please remove your socks before sex. Its just so weird to see someone like, fully naked but still wearing socks that it can really take you out of the moment.
Let's sum up the lessons here on how to give a girl oral sex that's going to bring her to climax and make her scream (from pleasure, unless you push the clitoral hood back too soon): Before you start to please her, tease her and the more of this you do, the more anticipation you build, and the more desperate she will be to experience your
If done right, your fingers are able to give her extreme pleasure and make her ready for your penis. Once shes ready start introducing only the tip of your penis, stop for a little bit to give her time to get used to it and relax, and then insert it a little bit further, stop and go further again as much as she can handle.