Just wondering if you are circumcised, and if so has much of the inner skin been removed. You might want to try using lube such as KY liquid for both masturbating and vaginal sex. If it's not related to being cut, perhaps you're feeling guilt; this can be a great cause of impotence. Consider your feelings and work on being positive about sex with your girlfriend and alone.
Well, no i am not circumcised.
Yea, that's something I've been considering of feeling guilty, that I've been failing on the main point but at the same time its everything just fine until we actually get going on the sex and oral parts. Its all hard and fine until just then.
Ok, this sounds like something I had trouble with the first bit my girlfriend and I had sex. It was my first time and I have a horribly overactive mind. I had to learn to NOT think about what I was doing. Thinking too much during sex can cause you to become flacid. I am not saying that this is your issue, but its a possibility. If you find your mind focusing too hard on what you are doing or straying off to other topics, try to reel it in. Just enjoy the moment. Live right there in that time and let everything else go. Sounds cheesy, but it worked wonders for me! :)