It sounds like your issue is an insensitive girlfriend whom you're way too good for, and Premature Ejaculation. Check out the sticky for more information on that! As for your girlfriend, dump her, or withhold sex. I bet she won't complain about you being "small" (which you're not by the way!) if she's being denied sex.

You are exactly average! That means MOST men in the USA are EXACTLY the same size as you are!

5.5 is not small. Don't worry about it. It's normal- And if a girl isn't satisfied with that she needs to learn more about her own body.

Really thanks for the reply.
well i think she is cool with the size its just my penis is too thin i guess, well the bottom part of it is really thin than the front part. Because when it gets hard the Glans gets big but the shaft and the down still remains thin.Even when i touch it i cud feel how thin it is. And Also it doesnt be straight when it is hard it falls down in left side. And I think my scrotum is long. I used to muster bate a lot in my high school. Is it the effect of that? and is there any ways i could make it thick and keep it straight?

No the masturbation doesn't have anything to do with it. Don't worry about that. And they're not all straight either, that's normal too.

Don't try anything to make it thicker! Anything that might just sounds dangerous. Here's a trick- while you're in there, move in a figure 8 with your hips. That way, your penis will stimulate everywhere and it should feel really good for her. If she's on top, grab hold of her hips and move her in this way too. It will feel good if she wants it thicker, because what she really means is that she wants stimulation all around, you know what I mean?

It really isn't the size of the ship....

You sound like you just need to be more confident! Good luck.