Hi. I have a normal penis but i feel it's a bit small. . When fully erect its about 4 inches nd sometimes 3.5 inches. I also ejaculate within 30 seconds when I'm really excited. I tried to have sex with my girlfriend and my penis would barely go in. We weren't in a comfortable position of spreading the legs though.. Is my penis very small to penetrate . What can i do to increase its size and to last longer. Pls help.