It's all in how you use it. I cant understand your situation because I'm roughly around 8 inches erect but I can tell you from personal experience that I have to be careful how I am stroking some girls. I can imagine with a smaller penis there is more wiggle room to be a little rougher and harder.
You don't need a 10 inch penis to satisfy a woman. In fact size queens are very rare. I'm only 8 and every single women I have been with has squirted or creamed.
The same rules apply get in tune with a women's body which provides physical pleasure stimulation, stimulate her mentally be slightly dominate and she will cum guaranteed.