I think you need to relax and not worry about whether you come or not as anxiety will reduce your pleasure, just enjoy the act of sex itself. Second if it is the beginning, you might feel a bit painful when you have sex as your vagina stretches to accomodate the penis. And third not all girls orgasm from vaginal sex alone, you need some clitorial stimulation either by change of positions (girl on top is a good one) or fingers or oral. Don't worry too much about the G-Spot, most girls don't have it or feel a change because of it, personally I believe it is over-rated.

And yeah, try long drawn foreplay with a lot of stimulation and try to get as much aroused as possible before you start the actual sex part. It will help.

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