This has been addressed before. I think the main issue is that you have to re-condition the sensitivity of your penis.
A vagina will not have near the pressure/grip as say your hand. You have conditioned yourself w/ masturbation to need a lot more pressure and pumping. Sex isn't equal to that.
Maybe try lessening masturbation or at least the grip you use when doing it... see if that helps.
Also, try different positions that can make penetration feel different.

Welcome to the SI101 Board and its Forums, I hope you enjoy participating. Please begin by familiarizing yourself with the FAQs, the Posting Guidelines section, and especially the Index, all found at the top of the main screen. The Index contains links to helpful informative insightful as well as how-to articles. I recommend that you and your girlfriend begin reading from the top of Page 1 to the bottom of Page 2. Knowledge is empowering and these articles were written in part to help make life and love easier than it was for those of us who have gone before. In addition, by reading all of the articles, you will likely find answers to questions you did not know you did not know.

Before I begin, please do not use all caps when typing. ALL CAPS ARE more difficult to read and also amount to SHOUTING in internet messaging.

> WHEN IAM INSIDE HER THERES LIKE NO PRESURE I CANT FEEL ANY TIGHTNES. I HAVENT EVEN CUMMED YET BECAUSE I HAVENT ENJOYED IT. WE TALKED ABOUT IT AND WE THINK WE ARE DOING SOMETHING WRONG. BUT I HAVE NO IDEA WHAT WE ARE DOING WRONG.

There is a trend nowadays in which guys have the misguided misconception that the best way to an orgasm is from lots and Lots and LOTS and LOTS of stroking. Wrong! This is why people used to devote so much time to fooling around and making out. As a guy you need and want to be on the raw edge of loosing control before entering your partner. You do not want to be so close to the trigger point that you lose control while shifting around getting into position, yet, not be so far that it's going to require a whole lot of humping to rebuild the peak of your arousal.

Also, you want wait on penetration until being invited, directly or indirectly. Your girlfriend should have the first and the last (if she desires) orgasm, assuming she has learned how to climax. This is just etiquette and good manners.

Not many positions place a woman's pieces parts in close constant contact with a man's pubic mound sufficient to build her arousal and trigger a climax; therefore, what a knowledgeable, skilled, caring, lover will do is to reach around and finger her while stroking/thrusting.

How long are the two of you spending making out before getting to foreplay? If it is less than half an hour, the two of you need to do it longer. Unlike males of the species who can be ready for sex at the drop of a hat or the mere idea of it, women usually require a prolonged buildup, so plan on doing between half an hour to forty five minutes necking, petting, and, heavy petting, before moving onto foreplay and then intercourse.

Demon makes a good point about practicing masturbation using less pressure. Buy some lubricant like Astroglide or K-Y at a pharmacy or supermarket and use it when home alone. You will learn that it requires a much lighter grip and a lot less friction using a grazing action of your hand. Often your climaxes will be more intense, although, not like when the two of you are together! It shouldn't take too long to retrain your brain to the lighter touch.

A vagina will sometimes expand in diameter when a woman is aroused and this will reduce the friction. You can always shift position and try to find an angle that will rub more against the vaginal wall.

After reading the articles, please do not hesitate to ask questions. This is the why of this site.

It took you more than three tries to learn to ride a bicycle and sex in more complicated than that! Keep trying. Demon and Doc make good points. The vagina does balloon during sexual arousal and that reduces pressure and friction on the penis. If you are both rather fit, try this: With her on her back, enter and then switch her legs inside yours. This lessens depth of penetration but puts the thickest part of your penis about in the narrowest part of her vagina. This increases the stimulation of the penis and, as a bonus effect, causes the penis to rub directly over her clitoris.
This does not work for corpulent couples. All positions need be adjusted for the two bodies involved.